Strutinsky’s Shell-Correction Method in the Extended Kohn–Sham Scheme for the Investigation of Binding Energies of Atoms and Cations in the Ground State YA. I. DELCHEV, 1 A. I. KULEFF, 1,2 TZ. MINEVA, 3 F. ZAHARIEV, 4 J. MARUANI 2 1 Institute for Nuclear Research and Nuclear Energy, BAS, 72 Tzarigradsko Chaussee, 1784 Sofia, Bulgaria 2 Laboratoire de Chimie Physique, CNRS and UPMC, 11 rue Pierre et Marie Curie, 75005 Paris, France 3 Institute for Catalysis, BAS, Acad. G. Bonchev ul., bl. 11, 1113 Sofia, Bulgaria 4 Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z1 Canada Received 3 March 2003; accepted 10 October 2003 Published online 7 June 2004 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/qua.20051 ABSTRACT: We performed self-consistent calculations of the oscillating part of the ground-state energy of atoms and cations from Be through Ca, using Strutinsky’s shell- correction method in the framework of the extended Kohn–Sham scheme. New “transi- tion state” numbers in the Taylor series expansion of the ground-state energy are introduced, allowing the elimination of the second-order shell-correction term. We show that the application of this procedure yields practically identical results whether it is performed self-consistently or not, and even the first-order term of the shell-correction series gives a good approximation. Oscillations in the shell-correction energy of cations appear amplified with respect to those of the corresponding isoelectronic neutral atoms. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem 99: 265–276, 2004 Key words: Strutinsky’s method; extended Kohn–Sham scheme; shell effects; atomic structure; Janak’s theorem 1. Introduction A n ongoing endeavor in quantum chemistry and physics is to build a well-grounded the- ory that would correctly describe the energetic properties of multifermionic systems in their ground (and excited) state(s) and make it possible to perform a consistent splitting of the properties variations into two parts: a gross part, which would collect those features common to all related systems and vary smoothly with the system size; and a residual part, which would account for the individ- uality of each system and gather the characteristic Correspondence to: J. Maruani; e-mail: maruani@ccr.jussieu.fr International Journal of Quantum Chemistry, Vol 99, 265–276 (2004) © 2004 Wiley Periodicals, Inc.