title: Acceleration of self-consistent-field convergence by combining conventional diagonalization and a diagonalization-free procedure.
abstract: A new scheme that combines conventional matrix diagonalization with the recently proposed diagonalization-free algorithm has been developed to obtain the density matrix for the next self-consistent-field iteration from the Fock matrix of the current iteration. In this manner, the advantages of the two methods are combined. The more rapid convergence of the diagonalization-free algorithm for density matrices rather close to self consistence and the more robust convergence of the conventional matrix diagonalization further away from self-consistence. The scheme has been implemented in the one- and two-component self-consistent-field procedures in the program system TURBOMOLE. The number of iterations is typically reduced by about 10%, but savings are usually much larger for slowly converging cases.
authors.affiliation: Theoretical Chemistry Group, Institute of Physical Chemistry, Karlsruhe Institute of Technology, KIT Campus South, P.O. Box 6980, D-76049 Karlsruhe, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Baldes
authors.forename: Wim
authors.initials: W
authors.lastname: Klopper
authors.forename: Ján
authors.initials: J
authors.lastname: Simunek
authors.forename: Jozef
authors.initials: J
authors.lastname: Noga
authors.forename: Florian
authors.initials: F
authors.lastname: Weigend
mesh_terms: D000465:Algorithms; D011789:Quantum Theory