The Arrhenius equation is used to find the energy of these things, which is called the activation energy.
Algorithms for finding these things are tested on OptBench, which includes the LJ38 and Heptamer Island test cases. The "climbing image" method is a modification of an algorithm used to find these things which adds spring forces along a pathway. Lorquet's nonadiabatic theory of these things allows for nonrelativistic coupling to cause mixed states. They are most commonly found using the synchronous transit or (*) nudged elastic band methods, and they resemble the end state closest in free energy to them according to Hammond's postulate. They correspond to saddle points on a PES and are designated by a double dagger. The Arrhenius equation is used to find the energy of these things, which is called the activation energy. For 10 points, name these locally-maximal energy intermediates in a chemical reaction.
Algorithms for finding these things are tested on OptBench, which includes the LJ38 and Heptamer Island test cases.
transition state [or activated complex]