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Starting SCF calculations by superposition of atomic densities
Author(s) -
Van Lenthe J. H.,
Zwaans R.,
Van Dam H. J. J.,
Guest M. F.
Publication year - 2006
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20393
Subject(s) - open shell , superposition principle , hamiltonian (control theory) , shell model , basis (linear algebra) , statistical physics , atomic physics , chemistry , computational chemistry , physics , quantum mechanics , mathematics , mathematical optimization , geometry
We describe the procedure to start an SCF calculation of the general type from a sum of atomic electron densities, as implemented in GAMESS‐UK. Although the procedure is well known for closed‐shell calculations and was already suggested when the Direct SCF procedure was proposed, the general procedure is less obvious. For instance, there is no need to converge the corresponding closed‐shell Hartree–Fock calculation when dealing with an open‐shell species. We describe the various choices and illustrate them with test calculations, showing that the procedure is easier, and on average better, than starting from a converged minimal basis calculation and much better than using a bare nucleus Hamiltonian. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 926–932, 2006