Particle correlation from uncorrelated non Born-Oppenheimer SCF wavefunctions

TL;DR

This paper evaluates a nonadiabatic self-consistent field method using an exactly-solvable model, demonstrating its accuracy and revealing how coordinate integration induces couplings among internal degrees of freedom.

Contribution

It introduces and analyzes a nonadiabatic SCF approach with laboratory-fixed Cartesian orbitals, highlighting its accuracy and the effects of coordinate integration.

Findings

The method yields remarkably accurate results on the simple model.

Integration over Cartesian coordinates induces couplings among internal coordinates.

The approach effectively accounts for nonadiabatic effects in molecular systems.

Abstract

We analyse a nonadiabatic self-consistent field method by means of an exactly-solvable model. The method is based on nuclear and electronic orbitals that are functions of the cartesian coordinates in the laboratory-fixed frame. The kinetic energy of the center of mass is subtracted from the molecular Hamiltonian operator in the variational process. The results for the simple model are remarkably accurate and show that the integration over the redundant cartesian coordinates leads to couplings among the internal ones.