A simple way to test for collinearity in spin symmetry broken wave functions: General theory and application to generalized Hartree Fock

Journal Article · Sat Mar 07 04:00:00 EST 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4913740· OSTI ID:22416208

Small, David W.; Sundstrom, Eric J.; Head-Gordon, Martin ^[1]

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1. Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

We introduce a necessary and sufficient condition for an arbitrary wavefunction to be collinear, i.e., its spin is quantized along some axis. It may be used to obtain a cheap and simple computational procedure to test for collinearity in electronic structure theory calculations. We adapt the procedure for Generalized Hartree Fock (GHF), and use it to study two dissociation pathways in CO{sub 2}. For these dissociation processes, the GHF wave functions transform from low-spin Unrestricted Hartree Fock (UHF) type states to noncollinear GHF states and on to high-spin UHF type states, phenomena that are succinctly illustrated by the constituents of the collinearity test. This complements earlier GHF work on this molecule.

• OSTI ID: 22416208
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 9 Vol. 142; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CARBON DIOXIDE
DISSOCIATION
ELECTRONIC STRUCTURE
HARTREE-FOCK METHOD
MOLECULES
SPIN
SYMMETRY BREAKING
WAVE FUNCTIONS