Many-Electron Effects for Deep Levels in Solids: The Lattice Vacancy in Diamond

Abstract

The neutral lattice vacancy in diamond is simulated by the clusters ${\mathrm{C}}_4$, ${\mathrm{C}}_4$ ${\mathrm{H}}_{12}$, and ${\mathrm{C}}_{16}$. Many-electron effects within the ground configuration are estimated using the self-consistent-field $X\alpha$ scattered-wave method. The resulting term splittings are found to decrease precipitously as the size of the cluster increases, in contrast to the conclusions of Coulson and Larkins. It is concluded that in a real crystal these effects should, therefore, be small and that simple one-electron methods represent valid first-order treatments to the problem.