Kramers' theory for this phenomenon can be used to determine rate constants for various transition states in protein folding. One equation that describes this behavior utilizes terms with forces that do not rely on the properties of the heat bath by involving a memory function known as its namesake "friction kernel." In addition to the Mori equation, a one-dimensional model of this phenomenon that assumed an isotropic distribution of forces was developed by Smoluchowski. Another equation describing this process is a modification of Newton's second law and adds a time-dependent noise term and another description rewrites Fick's law of diffusion in terms of a probability density. Those models 
Kramers' theory for this phenomenon can be used to determine rate constants for various transition states in protein folding. One equation that describes this behavior utilizes terms with forces that do not rely on the properties of the heat bath by involving a memory function known as its namesake "friction kernel." In addition to the Mori equation, a one-dimensional model of this phenomenon that assumed an isotropic distribution of forces was developed by Smoluchowski. Another equation describing this process is a modification of Newton's second law and adds a time-dependent noise term and another description rewrites Fick's law of diffusion in terms of a probability density. Those models were devised by Langevin and Einstein, respectively. For 10 points, name this stochastic behavior of small particles suspended in a fluid.
Kramers' theory for this phenomenon can be used to determine rate constants for various transition states in protein folding.
Brownian motion