Core excitons in ionic crystals: II. Calculation of the Na LII,IIIedge in NaF

Abstract
For pt.I see ibid., vol.15, p.5033 (1982). The cluster approximation in the unrestricted Hartree-Fock limit is used in a computation of the Na LII,III X-ray edge in NaF. In these computations the appropriate boundary potential discussed by Kunz and Klein (1978) is imposed and is found to be essential. The results agree well with experiment. The authors discuss the basic correlation processes and argue that the agreement with experiment is partly due to a cancellation of two non-negligible contributions to the correlation energy. Methods for including these correlation effect are proposed.
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