A Feynman dispersion correction: a proof of principle for MNDO.

A dispersion correction is introduced and tested for MNDO. The shift in electron density caused by the interaction between oscillating dipoles in the London picture of dispersion is mimicked by adding a small r-dependent attractive nucleus-electron potential to the core Hamiltonian. This potential results in a shift in electron density similar to that used by Feynman to explain dispersion. The resulting parameterized self-consistent and inherently multicenter treatment (MNDO-F) gives good results for CHNO compounds that do not exhibit hydrogen bonds, which MNDO cannot reproduce. This "Feynman" dispersion correction is also applicable to Hartree-Fock and density functional theory. Graphical abstract The MNDO-F optimized geometry for a C-fullerene tetramer in a tetrahedral configuration.