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The Monte Carlo technique is used to study the vapor-liquid interface of cyclopentane, cyclohexane, and benzene. The OPLS and TraPPE potential fields are compared in the temperature range from 298.15 to 348.15 K (273.15-298.15 K for C5H10). A new method for the treatment of the long-range interactions in inhomogeneous simulations is used. When this new method is employed, the obtained values of saturated liquid density and of enthalpy of vaporization are equal to those obtained using the bulk isothermal-isobaric Monte Carlo technique. The values of surface tension become independent of the cutoff distance and they are significantly larger than those when only simple spherical truncation of intermolecular interactions is used.

The solvation of alkali and halide ions in acetonitrile and acetone has been investigated via the molecular Ornstein–Zernike theory using the hypernetted chain approximation. Theoretical Gibbs solvation energies and solvation numbers are compared with experiments and numerical simulations. The calculated single-ion solvation energies are used to check the hypotheses serving to split-up the measured solvation energies of salts into their single-ion components. The solvation structure around the ions is discussed in detail and shown to be strongly influenced by the solvent–solvent spatial correlations. The calculated interionic potentials of mean force are presented and used to compute ion-ion association constants which are compared with experiment. The influence of the Lennard-Jones parameters of the ions upon the calculated properties is emphasized.

The structure of a series of aqueous sodium nitrate solutions (1.9-7.6 M) was studied using a combination of experimental and theoretical methods. The results obtained from diffraction (X-ray, neutron) and molecular dynamics simulation have been compared and the capabilities and limitations of the methods in describing solution structure are discussed. For the solutions studied, diffraction methods were found to perform very well in description of hydration spheres of the sodium ion but do not yield detailed structural information on the anion's hydration structure. Molecular dynamics simulations proved to be a suitable tool in the detailed interpretation of the hydration sphere of ions, ion pair formation, and bulk structure of solutions.

Molecular dynamics simulations have been performed for liquid formamide using two different types of potential model (OPLS, Cordeiro). The structural results obtained from simulation were compared to experimental (x-ray and neutron diffraction measurements) outcomes. A generally good agreement for both models examined has been found, but in the hydrogen bonded region (2.9 A) the Cordeiro model shows a slightly better fit. Besides the evaluation of partial radial distribution functions, orientational correlation functions and energy distribution functions, describing the hydrogen bonded structure, have been calculated based on the statistical analysis of configurations, resulting into a new insight in the clustering properties and topology of hydrogen bonded network. It has been shown that in liquid formamide exists a continuous hydrogen bonded network and from the analysis of the distribution of small rings revealed the ring size distribution in liquid formamide. Our study resulted that the ring size distribution of the hydrogen bonded liquid formamide shows a broad distribution with a maximum around 11. It has been found that the topology in formamide is significantly different than in water.

We present a novel integral equation method for the calculation of fluid structure in the vicinity of a plane impenetrable wall. The theory is based on the well-known RISM equation and is capable of dealing with arbitrary interaction site model (ISM) fluids at a solid/liquid interface. In conjunction with several closure approximations, the equations are solved numerically and wall-fluid site density distributions as well as charge density, field, and potential profiles are calculated for pure water and aqueous electrolyte solutions with varying concentrations adjacent to an uncharged soft wall. The results show reasonable agreement with corresponding computer simulation data.

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