title: Direct Chemical Dynamics Simulations.
abstract: In a direct dynamics simulation, the technologies of chemical dynamics and electronic structure theory are coupled so that the potential energy, gradient, and Hessian required from the simulation are obtained directly from the electronic structure theory. These simulations are extensively used to (1) interpret experimental results and understand the atomic-level dynamics of chemical reactions; (2) illustrate the ability of classical simulations to correctly interpret and predict chemical dynamics when quantum effects are expected to be unimportant; (3) obtain the correct classical dynamics predicted by an electronic structure theory; (4) determine a deeper understanding of when statistical theories are valid for predicting the mechanisms and rates of chemical reactions; and (5) discover new reaction pathways and chemical dynamics. Direct dynamics simulation studies are described for bimolecular SN2 nucleophilic substitution, unimolecular decomposition, post-transition-state dynamics, mass spectrometry experiments, and semiclassical vibrational spectra. Also included are discussions of quantum effects, the accuracy of classical chemical dynamics simulation, and the methodology of direct dynamics.
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States.
authors.forename: Subha
authors.initials: S
authors.lastname: Pratihar
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States.
authors.forename: Xinyou
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Homayoon
authors.affiliation: Department of Chemistry and Biochemistry, Siena College , Loudonville, New York 12211, United States.
authors.forename: George L
authors.initials: GL
authors.lastname: Barnes
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States.
authors.forename: William L
authors.initials: WL
authors.lastname: Hase
mesh_terms: D004583:Electrons; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D011789:Quantum Theory