title: A surface hopping algorithm for nonadiabatic minimum energy path calculations.
abstract: The article introduces a robust algorithm for the computation of minimum energy paths transiting along regions of near-to or degeneracy of adiabatic states. The method facilitates studies of excited state reactivity involving weakly avoided crossings and conical intersections. Based on the analysis of the change in the multiconfigurational wave function the algorithm takes the decision whether the optimization should continue following the same electronic state or switch to a different state. This algorithm helps to overcome convergence difficulties near degeneracies. The implementation in the MOLCAS quantum chemistry package is discussed. To demonstrate the utility of the proposed procedure four examples of application are provided: thymine, asulam, 1,2-dioxetane, and a three-double-bond model of the 11-cis-retinal protonated Schiff base.
authors.affiliation: Department of Chemistry, Bowling Green State University, Bowling Green, Ohio, 43403.
authors.forename: Igor
authors.initials: I
authors.lastname: Schapiro
authors.forename: Daniel
authors.initials: D
authors.lastname: Roca-Sanjuán
authors.forename: Roland
authors.initials: R
authors.lastname: Lindh
authors.forename: Massimo
authors.initials: M
authors.lastname: Olivucci
mesh_terms: D000465:Algorithms; D002219:Carbamates / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000737:chemistry; D006573:Heterocyclic Compounds, 1-Ring; D007700:Kinetics; D011522:Protons; D011789:Quantum Theory; D012172:Retinaldehyde / Q000737:chemistry; D012545:Schiff Bases / Q000737:chemistry; D013499:Surface Properties; D013816:Thermodynamics; D013941:Thymine / Q000737:chemistry
chemical_list: D002219:Carbamates; D006571:Heterocyclic Compounds; D006573:Heterocyclic Compounds, 1-Ring; D011522:Protons; D012545:Schiff Bases; C010036:asulam; C079142:1,2-dioxetane; D013941:Thymine; D012172:Retinaldehyde
keywords: CASSCF; asulam; dioxetane; minimum energy path; retinal; surface hopping algorithm; thymine