Ion solvation in nonaqueous solvents on the Born — Oppenheimer level

Extended orientational correlation study for molecular liquids containing distorted tetrahedral molecules: application to methylene halides

The method of Rey [Rey, J. Chem. Phys. 126, 164506 (2007)] for describing how molecules orient toward each other in systems with perfect tetrahedral molecules is extended to the case of distorted tetrahedral molecules of c(2v) symmetry by means of introducing 28 subgroups. Additionally, the original analysis developed for perfect tetrahedral molecules, based on six groups, is adapted for molecules with imperfect tetrahedral shape. Deriving orientational correlation functions have been complemented with detailed analyses of dipole-dipole correlations. This way, (up to now) the most complete structure determination can be carried out for such molecular systems. In the present work, these calculations have been applied for particle configurations resulting from reverse Monte Carlo computer modeling. These particle arrangements are fully consistent with structure factors from neutron and x-ray diffraction measurements. Here we present a complex structural study for methylene halide (chloride, bromide, and iodide) molecular liquids, as possibly the best representative examples. It has been found that the most frequent orientations of molecules are of the 2:2 type over the entire distance range in these liquids. Focusing on the short range orientation, neighboring molecules turn toward each other with there "H,Y"-"H,Y" (Y: Cl, Br, I) edges, apart from CH(2)Cl(2) where the H,H-H,Cl arrangement is the most frequent. In general, the structure of methylene chloride appears to be different from the structure of the other two liquids.

Hydration of Molecular Anions with Oxygen Sites – a Monte Carlo Study

Equilibrium properties of molecular model water (in pure phase and in electrolyte solutions) are calculated with the help of spatial pair correlation functions, starting from classical molecular pair interactions. Simulations were performed for a new simple water model derived from combined quantum-mechanical and statistical calculations in a SCF/SSOZ scheme.

Ion hydration of molecular anions with oxygen sites such as nitrate and perchlorate ions is of special interest when compared with hydration structures of spherical atomic anions like the halide ions. The water structure around the different solutes, and their influence on solution properties, is discussed.