Coulomb operator

The Coulomb operator, named after Charles-Augustin de Coulomb, is a quantum mechanical operator used in the field of quantum chemistry. Specifically, it is a term found in the Fock operator. It is defined as:

${\displaystyle {\widehat {J}}_{j}(1)f(1)=f(1)\int {\left|\varphi _{j}(2)\right|}^{2}{\frac {1}{r_{12}}}\,dr_{2}}$

where

${\displaystyle {\widehat {J}}_{j}(1)}$ is the one-electron Coulomb operator defining the repulsion resulting from electron j,

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