Theory of Correlated Wavefunctions. II. The Symmetry Properties of Atomic Correlated Wavefunctions

Abstract

The conditions under which a correlated wavefunction for an atomic system can be an eigenfunction of angular momentum are investigated. It is shown how symmetry‐adapted pair‐correlated wavefunctions may be set up in which the pair functions satisfy the condition of strong orthogonality to the orbitals in the initial orbital approximation, and in terms of which the variational equivalent of the first‐order perturbation equation reduces to a set of uncoupled two‐body equations, one for each pair. The approach is illustrated by application to the lowest ³P, ¹D, and ¹S states of carbon and to the ground state of neon, the latter case being of particular interest as it shows how the separation of the orbitals into unique pairs is unsatisfactory when the orbital approximation contains a number of equivalent orbitals.