Корреляция поступательного и вращательного движения молекул воды в молекулярно-динамических моделях

Abstract

The motion of a rigid molecule in a computer model can be described as the sum of the displacement of the center of mass of the molecule and the rotation of the molecule around an axis passing through this center. The interaction of a molecule with its environment leads to a correlation between these movements. Earlier in [1], we studied the distributions of angles between the directions of the displacement vectors and the axes of rotation of water molecules, as well as between them and the internal vectors of these molecules. This paper describes the correlation of the magnitudes of these displacements, that is, the lengths of the displacement vectors and angles of accompanying rotations. The correlation coefficients of these characteristics are calculated for intervals of different durations at different temperatures and pressures, and the character times of preservation of these correlations are determined. We believe that the times found by us represent the lifetimes of the local environments of molecules. For water molecules, a change in the local environment is accompanied by a change in the structure of the nearest section of the network of hydrogen bonds, and therefore the lifetimes of local environments are close to the lifetimes of these bonds.