An implementation of a Kohn—Sham density functional program using a Gaussian-type basis set. Application to the equilibrium geometry of C 60 and C 70

Abstract

An implementation of the Kohn—Sham procedure with orbitals expanded in a Gaussian-type basis is presented. It has been built into the direct-SCF program of a TURBOMOLE package, from which it inherits the ability to exploit all finite point groups. While the one-electron and Coulomb part of the problem are handled exactly as in the Hartree—Fock case, the exchange-correlation part is treated by a three-dimensional numerical integration. The code is designed to exploit the sparseness inherent in the problem and nearly everything is done in terms of matrix operations. An analytic geometry gradient has been implemented on the same lines. Calculations on the equilibrium geometry of the fullerenes C 60 and C 70 are reported.