title: Combining Quantum Mechanics Methods with Molecular Mechanics Methods in ONIOM.
abstract: The purpose of this paper is 2-fold. First, we present several extensions to the ONIOM(QM:MM) scheme. In its original formulation, the electrostatic interaction between the regions is included at the classical level. Here we present the extension to electronic embedding. We show how the behavior of ONIOM with electronic embedding can be more stable than QM/MM with electronic embedding. We also investigate the link atom correction, which is implicit in ONIOM but not in QM/MM. Second, we demonstrate some of the practical aspects of ONIOM(QM:MM) calculations. Specifically, we show that the potential surface can be discontinuous when there is bond breaking and forming closer than three bonds from the MM region.
authors.affiliation: Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, and Cherry Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Thom
authors.initials: T
authors.lastname: Vreven
authors.affiliation: Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, and Cherry Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: K Suzie
authors.initials: KS
authors.lastname: Byun
authors.affiliation: Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, and Cherry Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: István
authors.initials: I
authors.lastname: Komáromi
authors.affiliation: Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, and Cherry Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Stefan
authors.initials: S
authors.lastname: Dapprich
authors.affiliation: Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, and Cherry Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: John A
authors.initials: JA
authors.lastname: Montgomery
authors.affiliation: Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, and Cherry Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Keiji
authors.initials: K
authors.lastname: Morokuma
authors.affiliation: Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, and Cherry Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Frisch