Energy-linearized variational cellular method for large molecules and solids

• Published in: International journal of quantum chemistry Vol. 91; no. 1; pp. 46 - 50
• Main Author: Nesbet, R. K.
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc., A Wiley Company 2003
• Subjects: energy linearization; multiple scattering theory; variational cellular method
• ISSN: 0020-7608; 1097-461X
• DOI: 10.1002/qua.10427

Multiple scattering theory (MST) is the mainstay of Kohn–Sham calculations of the electronic structure of solids and alloys. MST formalism solves one‐electron equations within each atomic cell, using a Green function to propagate solutions across cell boundaries, while standard methodology for molecules expands wave functions in a Gaussian orbital basis. An energy‐linearized version of MST (LMTO) is efficient but restricted to an atomic‐sphere model. Full‐potential MST extends the formalism to space‐filling Wigner–Seitz polyhedra. The variational cellular method (VCM) solves full‐potential equations, replacing Green‐function propagation (structure constants) by variational matching at the interfaces of adjacent atomic cells. VCM provides a common formalism for molecules and solids but cannot easily be converted to an energy‐linearized method. A new variational principle is derived here that extends the VCM to a straightforward procedure for energy linearization. This formalism eliminates false solutions from the VCM. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003