M. L. Antipova

The topological and dynamic characteristics of H-bond networks in water according to computer simulation results

The classic molecular dynamics methods were employed to calculate the topological and dynamic characteristics of H-bond networks in water with the use of various model potentials. The explicit inclusion of specific intermolecular interactions between oxygen and hydrogen atoms additionally stabilized tetrahedrally coordinated molecules and, as a consequence, increased their number in the system. The lifetimes of H-bonds were found to characterize high correlation of movements of nearest environment molecules.

The mean lifetimes of H-bonds in water supercritical states

The dynamics of H-bonds in supercritical water in the region close to the saturation curve was studied at constant pressures of 30 and 50 MPa and temperature 673 K. The mean lifetime of H-bonds and changes in the topological and dynamic characteristics of H-bonding in supercritical water caused by temperature, density, and pressure variations were determined by the molecular dynamics method with the use of the TIP4P-HB model potential.

The special features of H-bonding in supercritical water close to the saturation curve

A complex study of H-bonding in supercritical water in the region close to the saturation curve was performed at constant pressures of 30 and 50 MPa and a constant temperature of 673 K. The topological H-bond characteristics were calculated by the molecular dynamics method with the use of the TIP4P-HB potential. The calculations included the number of H-bonds per water molecule, the degree of H-bonding, and the distributions of molecules according to the number of H-bonds (fractions and the gradients of fractions of molecules with n H-bonds). Changes in these characteristics as the temperature, density, and pressure varied were studied.

New model pair potential for water. Effect of inclusion of specific O⋯H interactions on the topology and dynamics of the hydrogen-bond network

Classical molecular dynamics was used to calculate the topologic and dynamic characteristics of H-bond networks in water, using various model potentials. The explicit inclusion of intermolecular interactions of oxygen and hydrogen atoms leads to a model involving additional stabilization of tetrahedrally coordinated molecules and, as a consequence, increased number of such molecules in the system. The H-bond lifetimes point to a strongly correlated molecular motion in the immediate environment.

Parameters of models and conditional sensitivity coefficients of radial distribution functions for water calculated by molecular dynamics data

The influence of parameters of rigid models of the 12-6-1 type on the properties calculated in computer experiments, viz., radial distribution functions and internal energy, was studied by the method of step-by-step transform of the water models supplemented by calculations of conditional sensitivity coefficients.