STRUCTURE INVESTIGATIONS OF LIQUID CHLOROFORM BY STATISTICAL-MECHANICAL CALCULATIONS AND REVERSE MONTE-CARLO SIMULATION

The structure of liquid chloroform at 298 K is determined with Reverse Monte Carlo simulations. Three independent neutron and one X-ray scattering experiments are fitted simultaneously to obtain higher evidence in the structural results. The structure is described in form of atom pair correlation and angular distribution functions. Furthermore, the atom pair correlation functions are used to calculate a probability that gives the spatial correlation of atoms of neighbouring molecules around a center molecule. The results are compared with Molecular Dynamics simulations of chloroform from literature and a very good agreement between both methods is found. The aim to reproduce experimental results with statistical mechanical calculations based on site-site Ornstein Zernike (SSOZ or RISM) theory in combination with the HNC closure fails. The comparison between statistical mechanical calculations and simulations reveals the unability of the SSOZ theory to describe the short range order of liquid chloroform. SSOZ theory predicts correlations of the hydrogen atom at short distances which clearly are not possible in the real liquid.