Quantum Dynamics Seminar: Potential Energy Surfaces, Newton Trajectories and Catch Bonds in Theoretical Chemistry

Date

Feb 19, 2025

Time

4:30 PM - 5:30 PM

Speaker

Dr. Wolfgang Quapp

Affiliation

Leipzig University

Language

en

Main Topic

Physik

Other Topics

Physik

Description

The talk begins with a discussion of the problems involved in defining a reaction pathway, in particular the steepest descent, the intrinsic reaction coordinate (IRC) and gradient extremals (GE). As an alternative, we propose Newton trajectories (NT) [1]. An NT is a curve where the gradient of the PES points in the same direction at every point. Other definitions of NTs and further methods for different calculations are reported [2]. NTs connect stationary points of the PES, so they can be used to find saddle points. Another important property of NTs is that they bifurcate at valley-ridge inflection points (VRI). Application: NTs describe the curves of the change of stationary points under a mechanochemical force [3]. A special application is the study of so-called catch bonds: counterintiutive bonds that become stronger under a mechanochemical force [4]. Two example PES are explained. 1] W.Quapp, M.Hirsch, O.Imig, D.Heidrich, J.Computat.Chem. 19 (1998) 1087; W.Quapp, M.Hirsch, D.Heidrich, Theor.Chem.Acc. 100 (1998) 285. 2] W.Quapp, J.Theoret.Computat.Chem. 2 (2003) 385, and 8 (2009) 101. 3] W.Quapp, J.M.Bofill, J.Phys.Chem.B 120 (2016) 2644. 4] W.Quapp, J.M.Bofill, J.Phys.Chem.B 128 (2024) 4097.

Last modified: Feb 19, 2025, 7:38:19 AM