Relativistic central-field Green's functions for the Ratip package

Abstract From perturbation theory, Green's functions are known for providing a simple and convenient access to the (complete) spectrum of atoms and ions. Having these functions available, they may help carry out perturbation expansions to any order beyond the first one. For most realistic potentials, however, the Green's functions need to be calculated numerically since an analytic form is known only for free electrons or for their motion in a pure Coulomb field. Therefore, in order to facilitate the ... Title of program: Xgreens Catalogue Id: ADWM_v1_0 Nature of problem In atomic perturbation theory, Green's functions may help carry out the summation over the complete spectrum of atom and ions, including the (summation over the) bound states as well as an integration over the continuum [1]. Analytically, however, these functions are known only for free electrons (V(r) === 0) and for electrons in a pure Coulomb field (V(r) = -Z/r). For all other choices of the potential, in contrast, the Green's functions must be determined numerically. Versions of this program held in the CPC repository in Mendeley Data ADWM_v1_0; Xgreens; 10.1016/j.cpc.2005.01.023 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)