
Accession Number : AD0261225
Title : ON THE NONORTHOGONALITY PROBLEM FOR INTERACTING ELECTRONIC SYSTEMS
Corporate Author : UPPSALA UNIV (SWEDEN)
Personal Author(s) : MCWEENY,ROY
Report Date : 15 JAN 1961
Pagination or Media Count : 1
Abstract : An electronic system may often be regarded as composed of two interacting subsystems. It is then possible to discuss the properties of the whole in terms of those of its parts, density matrix theory providing a convenient mathematical tool for this purpose. Earlier discussions, in which the wave functions of the subsystems were restricted so as to satisfy a strong orthogonality condition (and which consequently could not be assumed exact), are generalized to allow for nonorthogonality. As a simple illustration, the approach has been tested on the system of two helium atoms. This calculation, which is of a preliminary nature, serves to indicate the great importance of nonorthogonality corrections: these become exceedingly large as the subsystems begin to interpenetrate, and describe strong repulsions. It is hoped that this method of attack will prove of value in discussing the repulsive potentials between atoms and molecules in crystals and fluids. (Author)
Descriptors : *QUANTUM THEORY, ATOMS, CHEMISTRY, CRYSTALS, FLUIDS, HELIUM, HELIUM BOMBARDMENT, MATRICES(MATHEMATICS), MOLECULES, PHYSICAL CHEMISTRY
Distribution Statement : APPROVED FOR PUBLIC RELEASE