Calculating of the Cohesive Energy of Diamond

Publisher Website
Google Scholar
Abstract
It is well known that a satisfactory value for the binding energy of the hydrogen molecule may be calculated using a wave function which has the form of a Heitler-London (HL) function built on non-orthogonal orbitals. However, Slater has shown that a HL function built on orthogonal orbitals fails to yield any binding for the hydrogen molecule, but binding may be achieved by mixing with the HL function an ionized-molecule function which assigns two electrons to one atom and none to the other. Satisfactory results may also be achieved using a Hund-Mulliken (HM) function which may be built on either orthogonal or nonorthogonal orbitals, since the wave functions resulting in these two cases may be shown to be identical.