The potential energy component corresponding to the electrostatic interaction between each pair of charged particles:
where

is the
permittivity of a vacuum,

is the distance between the two particles, and

and

are the charges on particles

and

. In
molecular orbital theory, the electrostatic repulsion between the two electrons occupying the orbitals

and

. In the
Hartree–Fock method, the mean
Coulomb repulsion is determined by the value of the
Coulomb integral
Source:
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.