Locality and Sparsity of Ab Initio One-Particle Density Matrices and Localized Orbitals

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 102; no. 12; pp. 2215 - 2222
• Main Authors: Maslen, P. E, Ochsenfeld, C, White, C. A, Lee, M. S, Head-Gordon, M
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19.03.1998
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp972919j

The cost of Hartree−Fock and local correlation methods is strongly dependent on the locality of the one-particle density matrix and localized orbitals. In this paper the locality and sparsity of the one-particle density matrix is investigated numerically and theoretically, primarily at the Hartree−Fock level, for linear alkanes containing up to 320 carbon atoms. A method for the calculation of localized, atom-centered, occupied orbitals is presented and compared with the Boys' localization procedure. The atom-centered orbitals are ideally suited for use in local-correlation calculations. The connection between the size of optimally localized orbitals, the locality of the density matrix, and the onset of linear scaling is investigated.