COMPUTATIONAL INVESTIGATION OF THE INFLUENCE OF THE ENVIRONMENT ON MECHANICAL-PROPERTIES OF SOLIDS

Using modified MNDO and AM1 semiempirical self-consistent-field molecular orbital methods in the cluster approach, we investigated the environmental influence on the mechanical properties of solids. The computational approach of the chemical reaction coordinate was developed for the study of mechanical deformation. The modeling of different types of deformation was considered. To test the validity of the method, we investigated the mechanical properties of simple hydrocarbon chains and silica systems. Uniaxial deformation and bending were considered for the heptane molecule. Verification of the mechanochemical calculations for polypropylene was fulfilled by analyzing its vibrational spectra. It was found that the influence of active medium particles (water, hydroxonium ion, surfactant) may have caused a sharp decrease of the strength of silica and hydrocarbons. The atom-level mechanism and some qualitative characteristics of these processes were studied. (C) 1995 John Wiley & Sons, Inc.