A simple technique to estimate partition functions and equilibrium constants from Monte Carlo simulations

A combined Monte Carlo ~MC! simulation-statistical mechanical treatment is proposed to calculate the internal partition function and equilibrium constant. The method has been applied to a number of one and multidimensional analytical functions. When sampling is incomplete, various factorization approximations for estimating the partition function are discussed. The resulting errors are smaller when the ratios of the partition functions are calculated ~as in the determination of equilibrium constants! as opposed to the partition function itself. © 1995 American Institute of Physics.