Improved implementation of Kirkwood-Buff solution theory in periodic molecular simulations.
Kirkwood-Buff (KB) solution theory is a means to obtain certain thermodynamic derivatives from knowledge of molecular distributions. In actual practice the required integrals over radial distribution functions suffer inaccuracies due to finite-distance truncation effects and their use in closed systems. In this work we discuss how best to minimize these inaccuracies under traditional KB theory. In addition we implement a method for calculating KB quantities in molecular simulations with periodic boundary conditions and particularly within the canonical ensemble. The method is based on a finite-Fourier-series expansion of molecular concentration fluctuations and leads to more reliable results for a given computational effort. The procedure is validated and compared to the original method for a nonideal liquid mixture of Lennard-Jones particles intended to imitate a real system, carbon tetrafluoride, and methane.
Nichols
Joseph W
JW
Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, USA.
Moore
Stan G
SG
Wheeler
Dean R
DR
D000465:Algorithms; D003198:Computer Simulation; D005466:Fluorocarbons / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D008956:Models, Chemical; D009991:Oscillometry / Q000379:methods*
D005466:Fluorocarbons; C035066:carbon tetrafluoride; D008697:Methane