Contraction of gaussian basis sets and the total energy of fcc copper

Abstract

A brief survey of contraction schemes for atomic, molecular, and solid-state calculations is presented. General guidelines for a simple application of the LCAO contraction procedure to solids are described with emphasis on subtle differences with the cases of atoms and molecules. By means of Wang and Callaway's program package, test computations are performed on fcc copper to produce non-self-consistent and self-consistent results. The electronic energies, densities of states, and x-ray scattering form factors compare satisfactorily with experimental results as well as with data obtained by Bagayoko et al. using a basis of 75 functions. The advantages of the contraction procedure include a factor of 6.8 savings in CPU time and a significant reduction in storage requirements. An extended version of the program package is used to compute the total energy of fcc copper for various lattice constants by a method recently introduced by Callaway and co-workers.