title: Mode-tracking based stationary-point optimization.
abstract: In this work, we present a transition-state optimization protocol based on the Mode-Tracking algorithm [Reiher and Neugebauer, J. Chem. Phys., 2003, 118, 1634]. By calculating only the eigenvector of interest instead of diagonalizing the full Hessian matrix and performing an eigenvector following search based on the selectively calculated vector, we can efficiently optimize transition-state structures. The initial guess structures and eigenvectors are either chosen from a linear interpolation between the reactant and product structures, from a nudged-elastic band search, from a constrained-optimization scan, or from the minimum-energy structures. Alternatively, initial guess vectors based on chemical intuition may be defined. We then iteratively refine the selected vectors by the Davidson subspace iteration technique. This procedure accelerates finding transition states for large molecules of a few hundred atoms. It is also beneficial in cases where the starting structure is very different from the transition-state structure or where the desired vector to follow is not the one with lowest eigenvalue. Explorative studies of reaction pathways are feasible by following manually constructed molecular distortions.
authors.affiliation: ETH Zürich, Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
authors.forename: Maike
authors.initials: M
authors.lastname: Bergeler
authors.affiliation: University of Hamburg, Institute of Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany.
authors.forename: Carmen
authors.initials: C
authors.lastname: Herrmann
authors.affiliation: ETH Zürich, Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Reiher
keywords: Davidson subspace iteration; Eigenvector following; mode-tracking; reaction kinetics; transition-state search