title: Exploring Copper Oxide Cores Using the Projected Hartree-Fock Method.
abstract: Coupled binuclear copper oxide cores are present in the active sites of some of the very common metalloenzymes found in most living organisms. The correct theoretical description of the interconversion between the two dominant structural isomers of this core, namely, side-on μ-η(2):η(2)-peroxodicopper(II) and bis(μ-oxo)-dicopper(III), is challenging since it requires a method that can provide a balanced description of static and dynamic correlations. We investigate this problem using our recently developed projected Hartree-Fock method (PHF). Here, the spin and complex conjugation symmetries of the trial wave function are deliberately broken and restored in a variation-after-projection scheme. The projected wave function carries good quantum numbers, has multireference character, and accounts for static and some dynamic correlation. Most importantly, the calculations are done at a mean-field computational cost allowing us to address large systems at a modest expense. The interconversion is studied here for the bare [Cu2O2](2+) core using a variety of projection methods (SUHF, SGHF, KSUHF, KSGHF). The results seem to be on par with much more demanding traditional multireference methods.
authors.affiliation: Department of Chemistry, Rice University, Houston, Texas 77005, United States.
authors.forename: Kousik
authors.initials: K
authors.lastname: Samanta
authors.affiliation: Department of Chemistry, Rice University, Houston, Texas 77005, United States.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Jiménez-Hoyos
authors.affiliation: Department of Chemistry, Rice University, Houston, Texas 77005, United States.|Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States.
authors.forename: Gustavo E
authors.initials: GE
authors.lastname: Scuseria