title: Linear-scaling implementation of molecular electronic self-consistent field theory.
abstract: A linear-scaling implementation of Hartree-Fock and Kohn-Sham self-consistent field (SCF) theories is presented and illustrated with applications to molecules consisting of more than 1000 atoms. The diagonalization bottleneck of traditional SCF methods is avoided by carrying out a minimization of the Roothaan-Hall (RH) energy function and solving the Newton equations using the preconditioned conjugate-gradient (PCG) method. For rapid PCG convergence, the Lowdin orthogonal atomic orbital basis is used. The resulting linear-scaling trust-region Roothaan-Hall (LS-TRRH) method works by the introduction of a level-shift parameter in the RH Newton equations. A great advantage of the LS-TRRH method is that the optimal level shift can be determined at no extra cost, ensuring fast and robust convergence of both the SCF iterations and the level-shifted Newton equations. For density averaging, the authors use the trust-region density-subspace minimization (TRDSM) method, which, unlike the traditional direct inversion in the iterative subspace (DIIS) scheme, is firmly based on the principle of energy minimization. When combined with a linear-scaling evaluation of the Fock/Kohn-Sham matrix (including a boxed fitting of the electron density), LS-TRRH and TRDSM methods constitute the linear-scaling trust-region SCF (LS-TRSCF) method. The LS-TRSCF method compares favorably with the traditional SCF/DIIS scheme, converging smoothly and reliably in cases where the latter method fails. In one case where the LS-TRSCF method converges smoothly to a minimum, the SCF/DIIS method converges to a saddle point.
authors: Department of Theoretical Chemistry, The Royal Institute of Technology, SE-10691 Stockholm, Sweden.
authors: Paweł
authors: P
authors: Sałek
authors: Stinne
authors: S
authors: Høst
authors: Lea
authors: L
authors: Thøgersen
authors: Poul
authors: P
authors: Jørgensen
authors: Pekka
authors: P
authors: Manninen
authors: Jeppe
authors: J
authors: Olsen
authors: Branislav
authors: B
authors: Jansík
authors: Simen
authors: S
authors: Reine
authors: Filip
authors: F
authors: Pawłowski
authors: Erik
authors: E
authors: Tellgren
authors: Trygve
authors: T
authors: Helgaker
authors: Sonia
authors: S
authors: Coriani