Note on Almost Closed Shells

Heisenberg's treatment of an almost closed shell is extended to electronic configurations consisting of several almost closed shells plus other electrons not in the shells. In this way Shortley's results are obtained with additional information about the nondiagonal matrix elements of the electrostatic energy. The results of calculating the electrostatic energies by this method are presented for the configurations p⁵p, d⁹d and d⁹p.