Relativistic all-electron Hartree-Fock-Dirac calculation of a quasi one-dimensional chain of selenium atoms

The relativistic molecular program MOLFDIR has been extended to calculate the energy band structure and electronic structure of infinite periodic systems on the basis of the ab initio four-component Hartree-Fock-Dirac equations. The first application has been performed for a quasi-one-dimensional linear chain of selenium atoms. The basis set for the polymeric calculation has been generated by fitting Gaussian functions to the numerical relativistic results of the atom with the help of the adaptive non-linear least-square algorithm. The relativistic energy band structure is compared with the ab initio non-relativistic Hartree-Fock result employing the relativistic basis set. (C) 1998 Elsevier Science B.V. All rights reserved.