So welcome everyone to our final webinar of this series. This is our 11th And if you missed any of the earlier webinars, please go to our field to fork website We now have 35 archived webinars available So today joining me actually in my office is Todd Weidman Todd has a master's degree in agriculture with an emphasis in horticulture from NDSU He's a lifelong gardener and he has a lot of experience in both traditional gardening and square foot gardening And he's really fun to listen to so I hope that you find what he has to say today useful So Todd come on over Thanks, Julie. There'll be a little extra something in your pay for that We're gonna get started here and it should be pretty good. I believe this is the last one. Yes, okay All right. We'll skip this part There's a short survey that you want to complete later. It's um, it's very easy to fill out I've done it so I think anyone probably could and you have the opportunity to win a prize for a dry Definitely worth your time to fill the survey out. I'm gonna start with this picture here It is a very typical raised bed using the square foot gardening method There is so much savings with when we'll get into that when you use this type of Method and also the added advantage that for example if it rains if you look at this picture You can see that you can walk right out there and I'm harvest or look at your garden and not be in the mud you're not pushing down the soil destroying the tilth and Each of these little squares of the zone and we'll get into that a little bit more Why would anyone want to do this? You can grow and and for example, you had a let's say a traditional garden where you have rows You do you grow about 100% of that garden in 20% of the space. So it's quite remarkable About a fifth of what it would take to grow in your traditional garden. You can grow in a raised or a square foot garden Type of a method you do a lot less work 2% of the work Not exactly sure if that's exactly accurate, but there is a lot less work You don't know if you don't know what size to start with I would start with a 4 by 4 Just to get going Many people like to do a 5 foot wide the reason you do a 4 by 4 or 4 foot by I have 4 foot by 10 feet and 2 and a half feet high the reason that it's 4 feet is because the average adult can reach out 2 and a half feet and You have it 4 feet You're not crawling in the bed if you have for example a 5 foot Many times I've seen people build these and they're actually crawling in the bed and kind of defeating the purpose of having the garden Many people wonder well, you know, I want to plant but I don't really know how to do it Is it just the absence of rose? Well, it is the absence of rose, but it also is if you take your garden package Seed for example where you buy your directions on your garden packet You look at that and it'll say for example nine inches between plants in the row So then you keep that nine inches away from all plants in the garden And if you know and then for example, if it's you don't have to worry about the roll part because there is no roll So you're actually using that space Here's a nice grid with a 4 by 4 garden sample 4 feet by 4 feet You have 16 zones in this and in each zone you could theoretically plant a completely different crop or flowers or vegetables And you quite well as well as you just pretended that in that one foot by one foot area That's where for example the top left say you planted all radishes in there Follow the directions on the packets how far apart a radish should be from the next radish in the row You can get quite a number of radishes in there now someone say what if I want to grow a tomato? A tomato will actually take up about one and a half in in two direction or three directions actually type of a thing so the tomato will take up quite a bit of the garden here But if you had something like beans, maybe you get maybe two in there or peppers Maybe three depending on the type maybe two and it's very nice and you save a lot that way Here's kind of a nice colored one. I Put this one after it so you can kind of see for example if somebody had oh Let's say you had little tiny things where you put them, you know 16 in a block versus one versus four versus two so you get a general idea of how the plants might look in your garden And each little square is a zone We're gonna touch on these areas here as we're going through the project or through the presentation a Lot of questions I get especially when it comes to seeds is what kind to get there's there's a big But big debate but there is a lot of Unknown or confusion as far as hybrid versus open pollinated or heirloom varieties Hybrid mesh then both have their their uses and both are are good in this depending on the situation Hybrid vegetables are very nice Yeah, the stronger plants disease resistant higher yield many times over the flavor is not as good or maybe not as sweet They're not as strong and they are very good for shipping But as far as a very nice flavor, you know, it's a tomato But it's not as good as a flavor as for example an heirloom tomato And I guess that's it's not personal, but I think that many people would agree with me on that Now open pollen and also with a hybrid They will not come true to form so if you plant a Hybrid vegetable many times it'll have an F1 on the on the picture or on the back indicating that it's a cross They will not come true to form so what will happen is say you all had beautiful tomatoes. They were fantastic It's a hybrid you save the seed and next to your plant them It'll be a tomato, but it will not be the same as the one you had and it will not be in most cases the same quality Now the open pollinated or heirloom different flavors different colors Almost a rainbow full of colors for these Very nice different flavors that you don't always find However, they are not as strong a plant tend to get lower yields Not as much for disease resistance insects seem to attack them or I plant both just to get a variety but The open pollinated or heirloom you can also save the seeds providing has a cross with something so if you had And let's say you had yellow pear Tomatoes and it didn't cross anything. It'll come back true to form is yellow pear tomatoes again next year And even if they did cross for example with another hybrid I mean another heirloom like Walmart or something you should get a nice F1 hybrid out of it I'm not sure what it would look like, but it would be a good plant also Saving seeds or not, you know if you do it right you can actually save some money if you do it wrong You have a season of a plant that is not Worth growing I've tried this before I've seen squash seeds that I I should have known head cross with other squash and what I get is Kind of a stringy chunky Almost unedible or inedible type of a fruit or squash from the plants Instead of one that some that I expected So if you have the time and you know what you're doing sure save seeds But if you don't and then that's where the very heirloom are open pollinated But if you don't they're really not as expensive if you think about it for example, like you get a package of carrots There's usually between 150 to 400 carrots in a package that cost anywhere from a dime to a dollar ten That's a lot of carrots. And so something to really think about Here's just some pictures of heirloom a lot of times they they throw organic in there But that's a completely different topic just because it says it's organic doesn't mean that it's heirloom a lot of times They're kind of slid in the same area Hi, Brad. We we discussed those and You can't see on this. I do have a I think a fuzzy picture that's coming up here with an F1 on it You know the very next picture if you close one eye you can probably see I'm above the carrot It says F1 and that means that it's a cross between one heirloom and another heirloom and they develop this really tough super Strong diseases that then I yielding carrot Look at the one on the right here Kentucky Wonder Beans are heirloom In almost all cases they will say whether or not they're heirloom or hybrid on there They like to both both both types of seeds on are usually have that on their on their on their package when you buy them Sometimes people like to plant things in containers It's like a little tiny raised bed or square foot garden if you know one foot by one foot container as you can see in the bottom Right here But if you do do that and you want to just start with that or you just want to start with these and move them out later There are some things to think about with your containers Which one is right a lot of times people will go by. Oh, that's so cute. You know nice little metal container there in the middle Metal tends to heat up in the sun and you can actually cook your plants with a with a nice metal container This is I can say cute because I have daughters, but this is a very nice little cute container The problem is though and if someone was here, I would ask them, but um, there is a problem with this container There was no drainage here. We have one with drainage, but It's um glazed over and with a clay pot a lot of times instead of glazing over before you said to do that They were for pulling the salts out of the soil So you'd have your plant in a clay pot for example, you'd water it next thing you're gonna get a white residue on the outside And that's very good for the plant not as nice looking for the homeowner, but very good for the plant We talked about drainage and I kind of gave away the next one here why water so water comes out the bottom The reason that you water so that water will come out of the bottom is that the water that we have here And in many areas has just a tiny little bit of salt in there And so if you're thinking oh, I'm gonna save water and not You know water so water comes out the bottom I will Guarantee you that after a while once you hit that water layer or where the water always stopped You'll actually create a salt water area and your plant will suffer or die from that Sometimes people will take the water that came out of the bottom and try to run it through again Um, you're just you're defeating the purpose of removing the salts by that Basically, you're just reapplying the salts and it will get salting and saltier as as time goes on Here's just a picture of some holes in the bottom of container Sometimes people will have containers and they'll say well then the soil comes out if there's holes in there What I do is I'll take a coffee filter just um I think they're Like maybe a hundredth of a penny each and they're very inexpensive and I'll stick that in there and that will stop the soil from from running out the bottom Different types of containers some of them you can actually plant so if you had your little raised bed square foot garden you could plant this and um the plants roots in theory will eventually break through this coconut core And um, you're done. You don't have to try to cut it out or dig it out of there Pete Moss has been around for a long time newspapers is one too that they're they're starting to Um, where you take like almost like a mortar pestle type of a device and make them Um, these will we'll also work for that commercially they they grow them in cells Um, I think it's usually 72 cells or so that there are there isn't a tray And they grow them that way and as you can see each one has at least two draining tools in the bottom If you like if you're into recycling, um, here's here's an example of where someone has taken a Melk carton cut it down made a little tray out of it. There is drainage holes in the bottom of it and Little happen is for example, these are onions The like a whole package was sprinkled in there when they're about this size they will take and cut apart the Plastic container and gently put them each in their own little pot or plant them in the cells of your raised bed garden and Um One thing what just a little aside here when you plant onions in there you plant them for example a couple inches apart and every Week you harvest three or four pretty soon. Um toward the end of the year You might even have to do a little bit more than that depending on how many put in there um You'll have just three large onions if you if you kind of space them out say okay This one this one on this one i'm gonna leave in there But as the time goes on i'm gonna harvest everything in this because it's gonna be too tight as the plant grows And that's kind of a fun way of growing onions Here's um another um, you know for commercial you can um put them in your pots like that The the container on the bottom of the darker black actually is a tray for collecting water and it's something that you could if you um Had plenty of water dump it out and not use it But these are getting close to being um re repotted not quite though. We'll get into that here Here's some little plants that are in a um Oh coconut core or peat moss type trays and um then they're separated out and and these can be directly planted right into your into your garden Here's a side view of those Growing in containers is very similar to growing in a raised bed. Um you need to have enough room If you put um for example two tomatoes in a container this size they um, they'll actually compete with each other like a weed Here's um just proof that it can't be done As far as uh raised bed same rules as a container We kind of went through that good drainage appropriate size. We're going to talk now about the the right soil and appropriate material for the bed Here's a nice little, you know raised bed type of um If you can see there they they've got a trellis and the the vine crop is growing up on that And so and you have a little raised bed um having a trellis in there is a nice way to grow your vine crops And I have even seen pumpkins growing on there. Their stem gets um quite thick or deep I guess um As far as the the diameter or circumference of the stem compared to a regular pumpkin grown on the ground But um they they will hang in in there if you're if your support is strong enough Here I went out and um got some pictures of raised beds They are a little bit um There's still snow on the ground when I took these pictures if you look at the one that's kind of in the right center That is a smaller one. Um, they're they're all four feet wide. Um, the one except for the tall one to the left That's a little bit narrower. They're four feet wide. This looks like a four by four bed and um very nice to work with Here's an example of somebody just throwing a little bit of wood in there to make it kind of an art As soon as the snow falls, I'm sure that there'll be a beautiful little raised bed there I'm not going to say where I took this but um it is in the area here If you live in the country or on a farm or what have you um, this is something I did when I was a Kid in high school or actually I'm just being in college my mom wanted raised beds And so I pulled all the stock tanks we had when dad was gone out to um a nice um, oh roll And um made a very nice area with them kind of hole in the bottom with an axe fill them with soil planted them and left and um, they're very nice for that They worked very well nice depth easy to you don't have to bend over anything and um after a couple years I was allowed to come back So it worked out all right What can they be made of um if you have um plenty of resources cedar of course fantastic It just seems to last forever. However, if you're like me a little bit low on the resources on pine pressure treated wood Pine is nice because it's very inexpensive even new and after it's done you can just um It just kind of rots. It's a very very inexpensive used pine Metal or plastic, um, I would go for something that was animal or food grade approved Any concrete or stone, but it gets kind of expensive and it's not really movable once you put it in there What not to use You're chemically treated contaminated wood Railroad ties all of these things have been have been known to cause problems with People's health when they eat the vegetables out of there I would not recommend it and if you had something like that I would definitely um Put in a different type of a system than these What should you use in there? Well, you can put almost anything in there. You have um, it's a nice type a personality type of project You can put in whatever you want. However Um, I recommend if if you're brand new at this, um, purchasing purchasing some nice, um, either just regular top soil or Some soil that's already been made by for example a nursery That they they have bagged up nicely with different types of things besides top. So they might have vermiculite or perlite some type of volcanic rock peat moss coconut core humus Yeah, I always say humus. It's not humus. It's humus um type of a there's there's just tons of different things they can put in there and so You can do that It can be expensive So I would shop around a lot of times I'll go to a nursery and say hey What do you use for yours if they had one there and they tell me and that's what I do and it always seems to work out good It's nice and clean. Um, and it's ready to use. You don't have to stir it You don't have to add fertilizer is and you can ask them if they have fertilizer But usually a lot of times it comes with that Talking about that a little bit one thing things to avoid bones meat and cheese It tracks rodents and I'm talking about rats and other other undesirable creatures Um, definitely don't put those in there. Um, you don't want to Um Be known as the place that has all the rodents basically um disease plant materials. Um, so nation, for example Your tomatoes peppers egg planted potatoes or an eight shade family You don't want to put those in there because they they share the similar diseases and you don't want that Basically to inoculate yourself with um a blight or what have you from a disease plant You know, you're rotated to one of their the cousins of the of the so nation. They're still more likely to get those diseases and Very very very difficult to get rid of weeds a lot of times people say, well, I'm going to throw weeds in there They have a use however if your weeds have for example seeds on them You are making a really big problem or for example in the summertime So you're cutting up a purslane weed. You throw it in there. It's almost like a starfish You cut it in 10 pieces. You'll have 10 little purse lanes growing. Um, so I won't recommend putting weeds in there Chemically treated grass clippings. For example, you spray it along for dining lines This little what have you um a lot of times that will hold on to that On the on the grass clippings and then when you put grass clippings on your garden that you've treated with Whatever type of broadleaf killer you've now inoculated your garden The majority of the plants that you plant out there will be broadleaves and um You have a number of different um mutations and undesirable results from that. So I wanted to use that Um wood chips seems like a great idea. However, the carbon and nitrogen ratio is um, I think it's 40 to 1 And so you have a lot of carbon for nitrogen and the little creatures the flora and the fauna Bacteria and what have you in the soil that's trying to eat the wood chips will actually Need a lot of nitrogen to break it down before they die and become plant food Kind of a circle of life or life cycle thing takes a long time if you had five years And you did the first year and not the next four it would work out really good But nobody really does that and so I would avoid wood chips A lot of times when you get it, um, it'll have nitrogen, phosphorus and potassium You're macronutrients that are in in majority of fertilizers and there'll be some some micronutrients You don't want to put a lot of the micronutrients on there You can get some mutated plants from that Dead plants um dead zones. How you know if it has nitrogen phosphorus and potassium More than likely you're pretty good. The other ones are such a low level that you need that. Um, it's a good chance. It's already in there Spagnum peat moss perlite volcanic rock. That's nice for um, lightning it up and giving it good tilt Giving a lot of um spaces for oxygen and water to percolate through there And so that's nice to help um loosen up the soil people who use coconut core Um, other, you know, extra topsoil. There's there's a lot of things you can put in there um So I guess what I would do is you find somebody that has one that that you really like ask them what is in there And then maybe consider that fertilizer a lot of times, um, I get questions people want to make their own fertilizer Like combining different types of fertilizer. It's it's just a nightmare Um, what I would do is just buy it at the rate that you like Like a 10 10 10 or 2020 20 you've got your nitrogen phosphorus and potassium and there's all there's a lot of different variations of that like like a 28 um 10 Two or what have you there's there's a lot of variations, but I would definitely um Personally if you're starting especially I would buy it. Um slow release or not slow release the slow release fertilizers are I love them I when I Start my garden in the spring. I'll put all kinds of slow release fertilizer according the directions out there And I'm done. I don't even bother. I you're you're done for the year It just slowly releases from these little pellets and works fantastic. I think If you are more advanced or or have more time you can go out and and personally, um at the right time of the year Fertilize your radish your your carrots your corn. What have you but um, I really don't have that kind of time And I really don't want to but I just use the slow release as far as organic or commercial I go whatever whatever one is cheaper and um seems to work out just fine Here's an example of um three numbers. This one just has nitrogen. So You see the point zero five zero zero. So that the first number is nitrogen and phosphorus and potassium Here's a picture of organic um fertilizer bat guano or bat droppings or bat whatever you want to put in there Another 13 Four and 13 for the nitrogen phosphorus and potassium mainly you follow the directions and it it works pretty good See we talked about this Light Love sunflowers and them And so As far as light your your best light for these is sunlight obviously and if it's outside and you've got a raised bed or a square foot garden Or are you in a traditional garden sunlight? Eight hours of sunlight you can grow almost everything A lot of people say well, it's really good sunlight. I don't know what that means So I've got two really good hours of sunlight So I don't you know to me if it's like two hours of sunlight and it's just sun And you have two hours of sunlight some other place and it's just sun It's to me. It's still the same sun and I don't understand where the good comes from Without it you get a lot of yield diminished plant death Sometimes I'll see people will plant a little garden or raise a bed of garden underneath a tree And I've always been wondered about that. Um, you know, I'll put um garden in a Direct competition with a very large plant that will steal all the water all the nutrients all the light And um something has to lose there. So don't put them underneath trees Here's when you're starting your plants. Um, the grow lights are a lot better than they used to be a lot lighter a lot cleaner and Very nice to work with easy to get But also movable so you can move them up and down I like to keep them anywhere between two or three inches above the plant and as the plant grows I'll I'll pull it higher not that I'm concerned that it's going to burn the plant But the plant will actually try to grow into it and then um, it's hard to separate the plant from the light bulbs as it's Kind of work its way around in there. So I would definitely keep an eye on Seedlings here's just a picture of six seeds that were planted Uh at different times and you can see is as it's growing and you might think well The one on the far right is ready to transplant and actually it's not um the two Leaves are not actually leaves that you see there But actually part of the cotyledon and they're they're providing food for the plant So I would not say I would say you definitely um shouldn't transplant yet here talked about this You don't want to fertilize into your true leaves form. It's kind of a waste of time It might it'll help a little bit, but I would wait to your true leaves form. Here's an example of true leaves There's a tomato If you look um, it almost makes like a t or an x the the two the two that are um serrated or lobed Type of leaves are the actual first true leaves. They came after the cotyledons or the pseudo or false leaves that you see on the sides and Now I would say you could throw a little fertilizer in there You might be wondering how much I would do about Maybe a half to a fourth strength just to get them started If you do too much and you kill them well, you're kind of out of luck So by doing half strength and then increasing as time goes on It goes pretty good, but once once a week or once every two weeks Hardening off. This is something that for whatever reason I hate doing It is the right thing to do You have your plants growing you want to move them out You do need to give them some time to grow In a little bit harsher environment you're protected a very Safe environment with nothing bothering them ever always getting the right amount of food water You move them out to the harsh climate of the outside and they can die So what I would do is um I like to take them and put them in the shade underneath some shrubs or in the shade Underneath the deck or someplace where they're outside but the shade and maybe a little breeze hits them And then the next day a little more and a little more and after about a week or so Depending on how fast you want to get them out. They should be ready to The plant biggest thing is don't let them dry out. They are Used to being in a non-windy environment and they can dry out quite quickly So you'll have to check them a few times during the day to make sure they're not dry Not drying out If someone was here, I would say, um, are these ready to transplant or not? I cast Julie but she's being nice to me. So I won't torture her with this today Um, obviously not. You can you see some of them haven't even come up yet. These are not ready to transplant. They don't have the trees Here's a couple of publications that um, I think are very good that would help you with this presentation They are linked on the site and um, what worth your time to to look at Here's a picture of this again. Um, just to reiterate what we went through if you look it's um, non-treated wood And I would say this is probably I'm just guessing, you know between You know foot and a half two feet high It's it's marked off in zones. And so it's got One two three four five six seven eight by four. So there's 32 zones here Very nice area. Obviously it's four feet wide. Um, you don't have to do this string method I have done both ways. I like the string method because to me it's like, yeah, I got a little zone out here But it really isn't required for that And you could in each zone you can plant something different and it's very nice or you can plant the same thing It doesn't really matter. I like to when I do this here I like to throw a flower in there once in a while just for something a little different And um, make sure the biggest thing is to follow direction with that now, you notice there's no There's no tilt problem because you're not actually climbing into the bed You come from the side you have weed in there. You just pull it out throw it on the lawn and grind it up later with the lawnmower Then you water you you save a lot with water and fertilizer and sunlight isn't wasted because the plants don't have rows where that's all wasted on You control the type of soil and fertilizer that goes with this also so Very nice way of doing it. Are there questions? You can type in the chat. All right Let's see here So if anyone has questions if you want to take them in the chat if you if you've fallen asleep Maybe tell me what temperature it is where you're at now but um, otherwise I'm I'm ready to be grilled for questions on raised beds or square foot gardening One thing that doesn't work well in these types of gardens. I found is corn Corn needs several other plants for pollination and a nice block If you plant corn in a row you do not get a good yield Maybe these kernels won't get pollinated because it's been pollinated. So corn doesn't do well in here You know in certain large vine crops that will wipe out your garden There are also plants that you won't want to put in here. I know Sometimes people have you know, for example, I what I do is I'll grow them on a trellis that's hooked onto the bed For example, my cucumbers and they stay off the ground nice and clean And they they do well on a trellis and in pole beans too, obviously So you can save a lot of space by um by trellis and in these little square foot raised beds How many tomatoes can I plant in a four by four square? Now four by four square I say I would say that you probably get Maybe two Tomatoes in there.  Have you tried combining raised beds with low tunnel production to grow vegetables almost year round I have um, my wife actually bought me a low tunnel this year and we stuck it out the other night As far as year round, um, that would um, they would freeze hard as a rock in the wintertime You know, it just It wouldn't be able to handle our our cold hard winters But if you had a low tunnel you could get an extra two weeks of growth in this in the beginning And two weeks of growth in the end of the year right around there, you know, not exactly maybe so, you know between a Three-fourths of a month and a month extra growth on that What is your oops should you rotate crops between raised beds on a yearly basis? Um, I'm very strong. Um proponent of rotating your crops And so if you have a little sheet of paper you can make a map And say for example, you had beans and peas and carrots here Next year and you want to throw a tomato in there, you know, I just rotate it And you break the disease cycles and insect cycles that are there. So yes, I would definitely rotate crops every year What's your thought on the use of germinating mats for seedlings? When do plants come off the mat? I like a germinating mat for seedlings. So what is that? That is a Basically, it's almost like an electric blanket, but it's not it's a plant that or a mat That's for growing that you put underneath your seedlings when they're starting Gives it a nice warm temperature and the plants just take off I would you know, for example, if you're if you got your first First or second set of true leaves I would take it off then Just to kind of tough them up for the outside world as far as when to when to take it off Best method to keep rabbits and gophers out of raised beds A lot of times the raised bed itself will keep out the rabbits of the gophers Maybe not the gophers up, you know, for example, I have a two and a half foot high raised bed And I also have a A foot high raised bed and the two and a half high one. I've never had any Animals in there. Now the foot one I have I've had rabbits and And more rabbits in there, I guess the best thing for that would be fencing you can buy different products Plants skid sometimes helps Sometimes the smell is so harsh though that you wish you'd never done it my opinion and then also dried blood and get that from the nurseries and Probably dried blood though. It seems to attract dogs And so if you have dogs, they'll always be jumping around in your garden Not as fun as you think So I would say you know chicken wire, which is unsightly is a nice way of doing it But a lot of times people don't want to do that because of the unsightliness but maybe that'll become a popular thing and Everyone can do it. So any other questions these are These have been real mind-stimulating and and good I'm sure that there's probably a few others that are starting to wake up now. So if you We have some more questions you can sure ask. Otherwise Well, one other thing for creatures as far as keeping them out of there one year I planted in my regular garden I put in sweet corn and I put in 10 rows of sweet corn and it just never came up I thought all of the soil was too cold and it rotted. So I replanted and Other week went by nothing and I it's like, where is this going? I dug down. I could not find a single seed And so after the fourth time I replanted the sweet corn I turned around and looked in all the morning doves in the neighborhood just flew down and went right down the row and ate every kernel of corn I put out there and so I went out and um got some chicken wire and I planted it immediately put chicken wire over the top of it And um, they just sat on the on the chain link fence next to include include we cannot get at it and um Probably not the best for them, but um They had eaten so much corn now they could barely fly. So It was pretty good We'll raise beds require less water in the traditional gardening methods They will require less watering instead of like for example, let's see water in traditional garden Your um, your water will go in between the rows, which is a huge waste Or for water It just can't be helped you could try and do like um, for example, all different types of watering tapes and such but if you um, just water traditionally with a sprinkler or I don't think anyone does floodgarden in here, but um with a sprinkler. There's a lot of waste with that I would say, you know, I think um At least a 20 percent I would say um for me more realistically for me. I guess it'd be more like a 50 percent savings in water with Um with watering in the raised bed just because um, not maybe with a square foot method now with a raised bed Okay, I think I spoke wrong there that that was for a um square footgarden Now with a raised bed, you actually have to water a little bit more The reason being is that it um dries out quicker and so that's um That's why you'd probably do a little bit more. You'll figure it out and go from there We've had great success raising garlic in raised beds Um, I've had some success too as long as um, I've grown in the middle sometimes when I've grown it toward the edge of the bed The the roots of the garlic has gotten cold and the garlic has actually Not come back or rotted over the winter or in the spring So if you're gonna try to plant something like garlic I would try it in the very middle of the raised bed and then kind of branch out from there Just keep in mind that it's possible that it'll die One thing too a lot of people don't realize a little aside here that you can grow garlic here You harvest the usually I harvest my garlic in first part of july And then I'll I'll take it. I'll brush it off. You don't wash it and I'll stick in the garage in a cool Not really cool, but a dark place After I brush out the soil and then it'll dry up a little more and I'll brush off more soil And then in the fall probably about october I will break them apart and the really big healthy ones I'll plant And the rest I'll eat and start up the cycle again But once again rotating that is is the way to go any other questions if not, um We'll just wrap this up and make sure you do your surveys so that you win Well, thank you again everyone for joining us. Um By the way, my name is julie garden robinson and I've been coordinating this series And we're especially interested on the survey in you telling us what future Future webinars that you're interested in that's how we get the ideas So please check out those archived webinars and all of the various nutrition food safety and horticulture publications We have on the field to fork site And I think we'll wrap it up for today I'm sure Todd would be delighted to hear from you in the future if you have other questions He'd love it. So thanks again everyone and Hope to catch you next time that we start our webinar series probably in the fall or for sure next winter Thanks


This paper presents a comprehensive methodology for evaluating the economic impact of earthquakes on transportation networks. It combines geographic information systems, GIS, probabilistic seismic risk analysis, and traffic simulation models to estimate the direct and indirect costs associated with damage to bridges and increased travel times. Additionally, it considers the social cost of reduced accessibility caused by disrupted transportation routes. This framework was tested on a realistic bridge stock in central Italy, where detailed land use data were collected and a traffic model was calibrated. Finally, a shake map derived from a historical real seismic event was used to perform a probabilistic risk analysis. This article was authored by Alessandro Rasulo, Sofia Nardojeni, Azza Evangelisti, and others.


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are calling Mila plus at second order and I want to note that we are divided h equal to h0 plus v where h0 was sum of the Fock operator, Hartree-Fock orbitals as the starting point of h0 Eigen function okay. So basically our psi 0 0 the psi Hartree-Fock and e 0 0 is sum of the orbital. So I am using A as an index for occupied orbitals. Then we had e 0 1 which was psi 0 0 v psi 0 0 which is psi Hartree-Fock d psi Hartree-Fock and your v was essentially since h0 is sum of Fock operator v was sum over 1 by Rij minus d v Hartree-Fock one particle Fock at the attendance seat okay. So if I put this and apply Slater rule this was can somebody remember this value what would be just e 0 1 applying Slater rules who can tell. So v is just 1 by Rij this would be added to the orbital energies eventually to get total Hartree-Fock energy. So what is this value in terms of spin orbitals minus half yes sum over all a b right a b anti-symmetrize a b where these are the spin orbitals right. So minus half this if you add this to the orbital energy you will get the total because e a was h a a again in terms of spin orbitals I am writing plus sum over b a b anti-symmetrize a b. So you had the b 2 so a is not summed up of course for orbital energy of a when I sum the orbital energy of a this summation will come plus this is all a b if I add the first order perturbation correction you will get half of a b a b okay. So that will give you Hartree-Fock energy. So I just want to make sure that you understand in terms of Slater rule of course in terms of e not 0 it is size 0 0 h not size 0 0 and e not 1 is size 0 0 v size 0 0 so addition gives you Hartree-Fock energy that is of course easy to see. So your e 0 0 plus e 0 1 was the Hartree-Fock energy. So by our definition of correlation energy the e correlation starts at second order okay and then we went through the second order perturbation equation and we wrote an expression for the correlation energy which is the correction at the second order. So you can also call by our old definition just e not 2 e not 2 is nothing but the correlation energy at the first correlation energy contribution which is the second order because at the e not 1 there may be a value but then that just adds up to Hartree-Fock so our first correction terms comes from e not 2 and we derived the expression that it is 1 by 4 a b and r s where r s are virtual orbitals and a bs are occupied orbitals okay. So I hope to this point all of you can derive this was actually derived okay initially we wrote all excited determinants of h not but we found that the single excited determinants do not contribute because of Brillouin's theorem.  So then we have a factor 1 by 2 for this pair 1 by 2 for this pair we got 1 by 4. So I hope all of you remember this derivation so the homework essentially starts from here. So please give it on Monday that you have to now write this anti symmetrized integrals in regular integrals and write an expression see which are equal use the symmetry to make sure that you just do not should not just expand and one line that expands in is one line I can also do a b r s minus a a b s r r s a b but try to simplify in terms of regular integrals which is still in terms of spin orbitals then do a spin integration. So that was essentially so eventually land up into a correlation energy for in terms of special orbitals both for the occupied and virtual orbitals you have a special orbital remember the entire thing is of course done for ground state a closed shell. So essentially a closed shell system where the Eigen function of H naught is a single determinant in fact all Eigen functions are single not only that is a single determinant which turns out to be a restricted essentially means it is a closed shell so that is that has been the requirement for deriving this particular formula however if it is a single determinant and not restricted I told you there are other Hartree-Fock like unrestricted Hartree-Fock restricted open shell a similar derivation can be done it is not really a problem but I am just telling that this particular derivation is follows the restricted determinant restricted Hartree-Fock return. So you essentially get this as the first correction to the Hartree-Fock energy and that requires the in two electron integrals between two sets of occupied orbitals and two sets of virtual orbitals at this point there are spin orbitals but we will discuss what happens when you integrate and get this special orbital. So let us now go ahead and try to understand these I was yeah MP1 correction for unrestricted Hartree-Fock okay that will also we have still the same you know same situation first order anyway it will get back the Hartree-Fock because that is for a very simple reason you just add up H0 and V whatever is your size 0 0 your E0 0 is size 0 0 H0 size 0 0 E0 1 is size 0 0 V size 0 0 so if you add it up so that has nothing to do with anything okay in fact as long as you have this structure you will always get first order giving you Hartree-Fock or reference energy I would not call Hartree-Fock in that case in the case of UHF it is UHF but you can have a more complicated reference even then what you will get is a reference energy which is which is the size 0 0 H size 0 0 so that is what I call the reference energy yes so basically what I mean to say whatever you do these two quantities will give you size 0 0 H size 0 0 and as long as this is a reference function this is a reference energy so I am not calling it correlation energy and at least for a single determinant I do not call it correlation energy so whether it is RHF or UHF it does not matter okay so one of the things that we have seen is of course the importance of doubly excited determinant note that in this process of getting E0 2 we had first got size 0 1 which is the first order correction to the wave function remember size 0 0 is psi Hartree-Fock but we also got size 0 1 which is a linear combination of all eigenstates of H0 except Hartree-Fock correct so if when you when you did this we remember our first correction just like here was actually from the doubly excited determinant okay and so we wrote this as psi ABRS and the matrix elements or the linear sorry linear combination coefficients for this determinants was this matrix element divided by epsilon A plus epsilon B minus epsilon R minus or essentially the difference of these two energies okay in a reverse order so this minus this so this is size 0 1 and actually if you remember by E our E0 2 was psi Hartree-Fock V psi 0 1 from there we got an original expression and then we applied slatter rules here so we can apply this slatter rule of course here just like we did here but that is not what I want to show what I want to show that the first order correction to the wave function which is the first important correction to psi Hartree-Fock to from the psi Hartree-Fock is actually starts from the doubly excited determinants the singly excited determinants which you might have guessed should be the first correction it does not come because the corresponding matrix element becomes 0 because of Brillouin's theorem so Brillouin's theorem essentially dictates that if you start from Hartree-Fock you have a Brillouin's theorem and then the first important determinant that contribute to the lowest perturbation order is actually doubly excited determinant psi ABRS so that is why I want to highlight the importance of doubly excited determinant and part of it will be discussed again when you do CI and is also the content of Synonal Glue's review that I had given you to read which is essentially known today as a pair correlation theory. So this is actually much broader perspective essential idea later we will see is that this correlation essentially means that I have two electrons let us say they are AB spin orbitals AB they get excited so this is somewhere here let us say I am just taking a two level system so one orbital two spin orbitals one orbital two spin orbitals so they get excited together to some RS to form what is called the doubly excited determinant so in a very graphical manner the two pairs are getting excited together to form doubly excited determinant they get excited essentially correlation essentially means they are getting excited so this is why in general it is called a pair correlation theory later we will see for a many particle problems we can have another set of pair which can also get excited and these two excitations can take place at the same time so time is of course here just for understanding but if it takes place at the same time what you will see is actually a four fold excitations which will come which will be a quadruply excited determinant but the probability of this taking place is nothing but since they are taking place simultaneously and independently will be a product of this pair and this pair so this is the content of the synonyms later pair correlation theory but at this point let us let us say that the more important determinants come because of the two electron excitations now why excitation is related to correlation now is one to tell very physically what does the correlation mean okay physically let us try to understand so you have an Hamiltonian and we are trying to solve the Schrodinger equation note that I have been mentioning this and this is a very important part of the correlation let us again understand two particle problem if I have two particles r1 r2 okay and in the limit of r1 tending to r2 which means the coordinates of the two particle of course the particles cannot be traced the particles have only a probability being anywhere but whenever the particles are at r1 and r2 what will first happen to the Hamiltonian so Hamiltonian can be defined for a given r1 and r2 right if you look at this Hamiltonian you have a 1 by r1 to term right so at r1 tends to r2 this 1 by r1 2 will become infinity so this is what is called singularity so this becomes in the limit a singular Hamiltonian if you have a singular Hamiltonian essentially means it is an infinite because 1 by r1 2 is becoming infinity and then normally for an infinite operator the wave function whatever the wave function is energy will become infinity it is just like multiplying an infinity times a finite number you get infinity so even if psi is not in infinite function it is a finite function since it is a singular operator when it acts on this this will become infinity so which means energy will become infinity of course such energies are not allowed we are looking at finite energy system so if it is a finite energy system then what is the allowed wave function so the allowed wave function for such a case when Hamiltonian is singular is that the psi of r1 r2 must go to 0 because that is the only way this can survive because infinity of course acting on 0 can be finite so energy can still be finite but the wave function cannot be finite I hope you understand it is just like a multiplication it is a very loose manner I am saying like infinity acting on a 0 can be finite but infinity acting on a finite is infinity so just like that the only possibility is that the wave function must become 0 so whenever these two particles come close together wave function becomes 0 what does it mean wave function is a sine of probability mod psi square is a probability so we can now make a statement that there is a vanishing probability of two particles coming together right so let us make this statement for the correlation energy that the probability that the two particles come together is 0 in any system because you imagine that they have they have only we can only talk in terms of probability so the vanishing probability probability or probability density of two particles coming together or you know in a very loose manner and this is how synonyl actually argues in a very loose physical manner that the entire all the n particles are actually moving they are colliding so whenever they come close together the probability is 0 what it means that they cannot come close together so in the Hartree fog let us see in the Hartree fog what happens if you look at Hartree fog let us say again two particle problem so so restricted Hartree fog a bar so that is my Hartree fog wave function right I hope you understand the terminology a is a alpha a bar is a beta so you have a restricted Hartree fog a is the 1s orbital or whatever so you have alpha spin you have a beta spin now obviously the two particles are in the same spatial orbital although their spins are different they are in the spatial orbitals so there is a possibility of the two electrons which are anti-parallel okay coming close to each other which means the then when I when I calculate the probability there is a probability of the two electrons coming close for anti-parallel spin however for parallel spins they are unlikely to come because their orbitals are different so they will avoid each other parallel spin so the real problem in the Hartree fog is that for anti-parallel spin this part of the exact nature is not being followed okay by the Hartree fog wave function so this is basically for the Hartree fog so in Hartree fog theory this there is a vanishing probability so how is that how is that done in the perturbation theory when you go beyond Hartree fog is that as soon as these two particles come close together they will anti-parallel spin they will try to avoid and the one way to avoid is to actually get excited so if you get excited at least there is a less probability of crowding please remember we are only talking in terms of probability so we can't say that there is there is that they will actually come or not come the probability is 0 so when you give a more space there is a possibility of avoiding each other if you have to send a crowded space if you look at n particles in a crowded space they are going to collide with each other so the virtual orbitals give you that space virtual orbitals essentially tell you that I can actually go away of course you may argue that if they are going away to two virtual or same virtual orbitals again opposite spin that is what the singlet does then again they will be together but the point is now the probability is being reduced there is a some probability of being here some probability of being here some probability of being here because there are so many virtual orbitals so it is only a question of probability it is whenever of course there is a singlet the two electrons will be in the same special orbitals with anti-parallel spin okay but if I have many options like I have only one option here in the Hartree fog A bar but now all RR bars which are virtual orbitals are opening up as an option so the probability gets reduced so essentially probability just gets reduced so that is how the argument of synonyl glue went again it is a very qualitative argument it is not a quantitative argument it is qualitative argument to understand what is correlation and why W excitedly important. The further argument that synonyl glue gives the single excitation are of course not important because of brilliance there so of course one can argue why not three particles and again synonyl glue had a very brilliant argument he said three particles in any case cannot come close together because they cannot be in the same orbital even in Hartree fog because of Pauli principle so three particles cannot come close together that is number one number two is that the V or the Hamiltonian which makes them correlate has only a maximum of two particle interactions so it has only one particle and two particle interactions because of cool off so it is very hard for the Hamiltonian to correlate three particles together so that is another argument that he gave that why three particle onwards is also going to be small why it is only the two particle which is important. So the entire correlation he said is dominated by what he called pair correlation theory and I think if you read this very nice you know synonyl glue actually told in physical terms what we will talk later about the couple cluster doubles and so on but after that he did not unfortunately as I told you he did not give a full rigor he gave a rigor to some extent but not the complete rigor he did not actually you know set out equations and so on and that was his weakness and then later other people came but the idea of the two particle correlation being the dominant correlation really came from the synonyl glue theory so that is why I just thought I will spend a few minutes though that is not really something that I would like to dwell those who are interested should read the synonyl glue paper advances in chemical physics it is a lot of other insights that you will get. So I think this is very important we will see this again in the context of configuration interaction that the doubles are important so we are first arguing that the wave function itself will have only pair correlated doubles and of course the wave function has doubles and energy will also have similarly E0 2 E0 2 can be obtained from this. So that is a triviality the point that we are trying to say that the size 0 1 contains mainly WXRA determinants and not triples why not triples of course by Slater rule you know why not triples but what synonyl glue did was actually to give a physical insight to this formula that is comes from the perturbation theory itself that synonyl glue need not do synonyl glue are good from a different point of view that there are two particles which can be in the same orbital in the Hartree form particularly the anti-parallel spins that is number one so they have to be correlated because correlation is essentially making sure that such things do not happen. So two particles should not come close together so then you have to give a space for them to go somewhere so they can go to any other virtual orbitals so that space allows them to avoid coming close together that is number one. Number two is that three particles onwards are unimportant because they cannot come close together by the same argument and the Hamiltonian is only two particles. So actually what synonyl glue is trying to do is to justify what you get from the perturbation theory by physical insight he is not using this because if you are using this anyway it is very clear I mean perturbation theory of course you will tell you first order triples cannot come because of Slater rules but that Slater rule itself is being justified in some other way you can say because he has not used this formula synonyl glue did not use perturbation theory so the arguments are much more qualitative and this actually are what it turns out to be couple cluster theory which is not really perturbative. So you will see so you do not use perturbation theory perturbation first order perturbation only justifies what synonyl glue had told that the pair correlation is important. So he is not using this so we will come back to this when we discuss the couple cluster again qualitatively please remember that we will we turn out to have classes we are not going to discuss very thoroughly many of these new methods but at least I thought the perturbation will discuss and try to give a justification of the synonyl glue theory. I had also mentioned in the previous class that if you do a restricted hard to reform let us say for hydrogen molecule for hydrogen molecule at a large distance so at r h h tending to infinity the e r h f does not become twice e hydrogen atom so this is something that I mentioned actually it becomes greater than the two hydrogen atom it goes to h plus h minus configuration and mainly that happens because of the spins remaining attached it is a singlet wave function so they remain attached to 1s here and 1s here. So let us try to understand this problem little bit better so remember my molecular orbitals are formed out of linear combination atomic orbitals which are my two bases so let us assume that those bases are 1s hydrogen A 1s hydrogen B again by the same nomenclature that original energies are identical when before the molecular start molecular form then you have the phi 1 and phi 2 are the two orbitals special orbitals that are formed these are the special orbitals molecular orbitals so I all of us know that one of them is anti-bonding one of them is anti-bonding one of them is bonding and the bonding orbital is let us say phi 1 so your Hartree-Fock then becomes or r h f then becomes phi 1 phi 1 bar correct so I hope the nomenclatures are clear so when I am calling phi 1 it is a MO for the interaction region so what happens for the psi r h f as r tends to infinity so let us as let us try to understand this as the r goes to infinity what happens to first phi 1 and phi 2 these are the special orbital both of them go to the 1s orbital that is clear right because they were started from 1s orbital and they had a bonding and anti-bonding orbitals if I do the reverse MO diagram then phi 1 will go to one of the 1s phi 2 will go to other one which one goes to where I do not know so the molecular orbitals become atomic in nature at r tending to infinity which is not surprising because there is no molecule at that point so when we say LCAO MO approach although AO's were used only as a basis since I am using the AO's there is a physical interpretation to this that these MO's will eventually become AO so that is where LCAO MO picture has a chemistry inside it is not just a basis so my 1s was not just a basis it has a physical inside that if I take this molecule apart these molecular orbitals will go over to these basis functions because they are atomic orbital basis I hope all of chemistry you know if I would have some use some other basis crazy basis then it would not have happened because eventually they go over to the atomic orbitals but because I have used the atomic orbitals and basis these phi 1 and phi 2 go over to the 1s hydrogen so then what happens to the wave function at that region so psi Hartree-Fock at r tends to infinity will then become 1s hydrogen A and let us say 1s hydrogen B bar correct because one of the phi 1s will become 1s hydrogen A phi 2 will also become 1s hydrogen A but now you have 1s hydrogen A 1s hydrogen B if they go separately or what is worse is that they mean they will more likely become this because both of them are phi 1 so if phi 1 becomes 1s hydrogen A then it will become 1s hydrogen A 1s hydrogen A bar and this is precisely the configuration which is H minus H plus because what is it show it shows both the electrons are in one of the 1s orbitals by chance if you can write this as phi 1 phi 2 bar then of course it will become 1s hydrogen A 1s hydrogen B bar but that is still not right because you know for a singlet wave function if I have a degenerate you cannot have this and this you have to mix okay so this is of course a singlet wave function there is no problem with this wave function this is a proper singlet wave function starting from a singlet but this is a wrong asymptotic behavior okay so wrong asymptotic behavior means it does not separate to the correct result because you know that if I have gas phase hydrogen if I dissociate it should become hydrogen atom plus hydrogen atom and not H minus H plus I hope all of you know this I have told this gas phase any diatomic molecule becomes A plus B not A plus B minus or A minus B plus okay never happens because ionization potential of any atom is greater than the electron affinity of any atom so you can never have A plus B minus is the ground state A and B together some would be much lower than A plus B minus because ionization of any atom is very high I mean you look at hydrogen ionization hydrogen ionization is how much 13.6 electron volt which is 300 kilo calorie roughly okay 320 whatever so no 300 kilo calorie I think 23 13 into 22 20 is 260 and 40 so roughly 300 kilo calorie which is already 1200 1300 kilo joules almost so you can imagine greater than 1200 kilo joules which is so high just to make H to H plus so H minus H plus will be so high how much of energy you can gain by H minus very little 1200 1300 kilo joules remember is larger than nitrogen bond breaking if you do a homolytic nitrogen bond breaking it is about 900 kilo joules CH bond breaking or hydrogen bond breaking is 400 some kilo joules we have done that exercise oxygen bond breaking is also 700 to 800 kilo joules somewhere 800 let us say nitrogen is about 890 or 900 but hydrogen ionization itself is more than 1200 kilo joules you know many times you do not realize these these numbers so ionization is so difficult okay hydrogen is of course quite large for other atoms it may even be less that is a different matter like cesium is most easily ionized but even then that number is very very large so that is the reason a heterolithic bond cleavage in chemistry is much more difficult than a homolytic bond cleavage so if I have a methane molecule I do a homolytic cleavage CH3 radical and hydrogen atom right that is much easy to do than CH3 minus H plus which is deprotonation right so deprotonation is much more difficult because it requires very high energy simply because of the hydrogen ionization that kills the problem so I just want to tell you why the H minus H plus is of course a wrong asymptote because in gas phase this is a very high energy so the ground state should actually go to H plus H which I am not getting so the question is how do you get H plus H singlet so let us try to see the wave function that we should get in the asymptote so let us look at what we should actually get in the asymptote so for hydrogen molecule again so the asymptote asymptotic singlet state so you had this phi 1 here you had the phi 2 here and this was my 2 1 s functions right is the usual curve that we plot so eventually each of these states will go to one of these which one goes where it does not matter so I will at the asymptote I will have these two states only what will be a singlet state I will have 1 s h a 1 s h b bar right but that is not enough I have already told you for a 2 electron singlet in a degenerate you have to do the other so you have to also add or subtract 1 s h a bar 1 s h b and of course with some combination that is not important okay in this case it will be simply 1 by square root 2 that is unimportant the point is with an overlap integral that overlap will anyway go to 0 okay at the r tending to infinity so we already know this in this case so it will become simply 1 by square root 2 but the point is the asymptotic singlet wave function is actually not a single configuration that is the first thing to understand you have what we call a multi configuration or 2 configuration in the asymptote okay it is a linear combination of 2 different determinants so I am calling it 2 configuration so either if you use r h n or even if you use u h n these are all single determinants as soon as I break them apart none of these will actually go to the asymptote correct though I had already mentioned that the u h f energy goes correctly but it is not a singlet that is a problem I am talking of a singlet state so the u h f energy goes correctly to the exact energy but then it is not a singlet so if I want a singlet asymptote of course u h f cannot give r h f cannot give even if I would have put phi 1 phi 2 bar as my determinant there okay you would still not get because you will get only one of these you would not get a linear combination so right in the beginning you have to start with phi 1 phi 2 bar and phi 2 phi 1 bar your original r h f original reference wave function then only you will get these as the asymptote is it clear but this is against the spirit of Hartree-Fock this is not Hartree-Fock right this is not Hartree-Fock because Hartree-Fock has always one determinant so the point that I am trying to mention that if I start with one determinant Hartree-Fock and try to split or try to separate the molecule I will never get the asymptote correctly okay and particularly I am giving an example of a singlet and I cannot get the singlet either way whether I do r h f and u h f though energy in u h f is close to the exact energy because of certain variation method that the energy goes down it comes closer but the wave function you will never get so if you want to get a proper singlet wave function you can see that the Hartree-Fock itself is not good so the question then we can ask is if I do a m p first order correction to the wave function remember when I say m p 2 that is for energy for the wave function what is the first order correction first correction at the first order correct so remember this do not say m p 2 for wave function also okay only for energy first order correction gives back with the zeroth order Hartree-Fock but as far as the wave function is concerned Psi 0 0 itself is Hartree-Fock and Psi 0 1 is different okay and that Psi 0 1 gives you e naught 2 because of that formula so Psi 0 1 has to be something different from Hartree-Fock okay so if you apply this we would like to know are we improving the system so if I just use a r h f I hope you understand the problem we will discuss that next class if I just use r h f 5 1 5 1 bar and then do a first order perturbation correction to the wave function am I improving the result in the asymptote so we want to discuss the behavior of Psi 0 1 as r tends to infinity okay along with the Hartree-Fock so it is important of course that my final wave function at the first order will be Psi 0 0 plus Psi 0 1 so the question that I am going to ask does it behave even qualitatively in r h h the region which tends to infinity again we will take only hydrogen molecule as a prototype case and we can even simplify the problem by taking a two basis so only we will take a two basis just like we did here 5 1 and 5 2 two basis so we will take the simplest LCMO we have one virtual orbital where you can excite both the electrons right so this r s can be generated because you have two special orbitals you have to force spin orbitals actually so we can very easily study this problem you can yourself try to do you know at your end what do you get finally what I am interested in this wave function when I add to the Hartree-Fock and then add to the Hartree-Fock wave function this first order correction okay so of course your a b r s will change because there are spin orbitals so let us say I have a and b are orbital this will become a a bar this will become b b bar I hope it is clear if a and b are special orbitals then this will actually become a a bar this will become b b bar in terms of special orbitals so I mean this is just nomenclature you can use some other nomenclature for special orbitals alpha beta whatever so the point is that you can easily study this model problem that am I separating hydrogen correctly because this is a very very important problem because if I am not able to separate hydrogen correctly there is something to worry how do I separate I already told you one way to separate would have been to start from this which means have a have whatever you call it reference or Hartree-Fock but it is not a single determinant Hartree-Fock it is a two configuration Hartree-Fock and this is a very important to understand all multi reference problems in quantum chemistry why multi reference problems comes as a reference so you can see my reference function itself should have been two reference function that is one way to definitely solve but if my reference is just 5151 bar then do perturbation like here does it help that is the question that we will ask if I of course start with this I know my reference itself is good enough at least qualitatively to separate but if I do not do that and I start with 5151 bar just as we are doing here for the Hartree-Fock and then do a first order perturbation shall I get the asymptote correctly I hope the question is understood because this is a very important question if I would have started with this anyway I would have got the asymptote correctly because this would become 1sa this will become 1sb vice versa rather matter both the determinants are there so first thing to understand that in the asymptotic limit the singlet wave function is of this form that is very important to understand I hope that is very clear because we have already given you a theorem that each of this determinant is not spin adapted please do not forget that theorem that if I have n alpha and n beta in this case n alpha n beta equal to 1 so one number of orbitals must be doubly occupied which is not true in either of these cases so these are now like molecular orbitals the same there is no difference between MO and AO at r tend to infinity so do not get confused so this determinant is not spin adapted this determinant is not spin adapted however a spin adapted wave function would be a combination of these two determinants and this is very simple to understand that I am saying that neither of this is correct but a combination of this is correct where this can be alpha or this can be beta this can be beta this can be alpha for a degenerate space this is correct and that is also physically right because we cannot pinpoint what is electron 1 and what is electron 2 electrons are indistinguishable so you cannot write like this you have to add these so obviously any one of these determinants is wrong but a correction term is right the question is if I start with phi 1 phi 1 bar can I generate that okay by doing a perturbation correction you can actually find the answer in fact you will get the answer itself yes psi a b r s means phi 2 phi 2 bar in phi 2 phi 2 bar in this case so what is asking is the psi a what is psi a b r s a and b are phi 1 phi 1 bar you have two state problem so there is only one virtual state so this is nothing but determinant 2 2 bar or phi 2 phi 2 bar so you can easily see whether the result will come or not actually the answer is no you can actually see this because I need phi 1 phi 2 bar plus phi 2 phi 1 bar I do not need phi 1 phi 1 bar plus phi 2 phi 2 bar so you know all since the question is already put it is very trivial to see that you will still not get it so that is a very disturbing thing that my r h f is not good for dissociation I do a first order perturb correction it is still not good okay and I will do it in detail but you can clearly see from the discussion it is still not good so what is good is actually to start from this there is no other way that means I do not do this I do not start from this r h f at all I do not start from any single determinant the original determinant original function itself is this and then I try to improve in fact very loosely I would say these are the basis of all multi reference problems like you have multi reference CI you have multi reference perturbation theory and so on okay so I think this is something that is qualitatively very important to understand because we cannot really spend a lot of time on multi reference because we are going to go back to single reference CI after this but I just thought I would mention why multi reference is important at least in one context of dissociation and these are these are very important problems where a molecule is closed shell but is dissociated into two open cell fragments I had given you this theorem that is when r h f fails if it was a closed shell molecule I do want to dissociate into two closed shell molecule then there is no problem so for example if I would dissociate h 2 to h plus h minus then it would have been no problem I want I do not want h plus h I want an excited state no problem because both of them are closed shells so the problem is whenever a closed shell molecule fragments into two open cell parts there is a problem and the problem cannot be washed away by simply doing m p 2 or first order correction to the wave function second order it cannot be washed away so we will see how do you handle such problems in fact we will talk not much about the multi reference so that is why I am just bringing the relevance of the multi reference why people still have to do multi reference most of the course we are going to do single reference starting reference functions are single determinant as we have done for the perturbation okay so what we will do now after discussion continuing the discussion closing it we will go to actually CI but I think what I like to do also is to describe this perturbation energy that we wrote E naught 2 of course in terms of special orbital by the time assignments will be due but more importantly how to represent them in a very convenient language and that is something that you should learn and that is called the diagrammatics there is a diagrammatic perturbation theory which means the same algebra that you are deriving in a very laborious manner and that is important at least from E naught 3 onwards the things will become more and more difficult how do I conceptualize these by drawing a simple diagrams and I have been telling these the diagrams are I told you certain diagram like scattering goes from 0 to excited state come back a more I would say a rigorous way of writing at least E naught 2 and E naught 3 in terms of diagrams is something that I will introduce introduction would be slightly ad hoc because to rigorously learn diagrams how they have come you should also learn what is called second quantization which also we will do later but I think next class I will I will in ad hoc manner I will introduce the diagrams and diagrams are very pictorial so all of you will be able to understand very easily there is no algebra actually so the maths there is no maths the maths is actually written in terms of diagrams so whatever we wrote E naught 2 that formula is written in terms of diagram and after that only we will go to CI so 2 configuration alone is not enough that is what I am trying to say if I write just 1s a 1s a bar 1s b 1s b bar that is also not enough then I then what I am doing I am getting only h minus h plus in 2 different ways once putting these 2 electrons here once putting but that is not enough for singlet I have to have in this manner if this is 1s a this is 1s b this manner which is not coming by the RHA which is not coming but even mp1 wave function first order corrected wave function and I think I will do that I will complete it but since the discussion already took place you can see the answer okay but I am just trying to tell you the context why people do in many many cases this is at least one context there are other reasons people do there are other cases where multi references also comes in but this is at least one and this is the simplest that I can tell you hydrogen nothing can be simpler than that hydrogen in 2 basis that is what you learn all your life but you do not realize what are the problems okay that it cannot sigma g sigma g bar is all that you have read it cannot dissociate if you add sigma u sigma u bar it still cannot dissociate that is what you are doing right by mp1 and that is what I will tell so because you need sigma g sigma u bar sigma g bar sigma u right so 1 alpha 1 beta 1 beta 1 alpha and that is not coming because each of your functions is just a singlet function to start with so if you are determinant itself is been adopted by adding you will not get this because each of them is not spin adapted here the combination is so this is a little bit of a physics here so this cannot be obtained by simply adding two spin adapted determinants no I hope you understand what I mean the combination is spin adapted although each of them is not so that is a part of the problem here so this physics is slightly complex we will have a discussion again in next class and then probably introduce diagrams before you go to CI okay all right.


Steph Ratharangi, Acting Chief Officer of the CFA. So I'm here today to say goodbye to the Victorian contingent who are now making their way to Queensland to help out with their fires. The situation in Queensland is significant, they have over 100 fires burning and a pretty challenging fire danger day today. So we couldn't think of a better way to get up there, hit the ground running and help out. So we've got 48 CFA firefighters heading up today with FFM Vic counterparts and colleagues from the SES. The roles that we're going to be playing are mainly firefighting on that urban-rural interface, tanker-based firefighting. So one of the first things they're going to have to do is get used to the new equipment. The rest of our contingent is made up from specialists, either IMT specialists, aircraft specialists, and we're assisted by Forest Fire Management Victoria in all of those roles. So I'm super proud of these people heading up today. Victorians know full well the impact of bushfires and the impact it has on the communities with such large-scale fires across Queensland at the moment. Our team can't wait to hit the ground, get stuck in and make an impact. Most of these people will only be heading up there for a week because we need them back home. So we've asked them to stay safe, rest up and be ready for their return.