Activation Energies and Beyond


Seminar

Date

Time

11:00 a.m.

Location

Zoom

Presenter

Ward H. Thompson (Professor, Department of Chemistry, University of Kansas)

Abstract

How the properties of molecular systems change with temperature is one of the most fundamental issues in chemistry. Knowledge of this behavior has not only practical implications, but fundamental ones, as it permits the separation of energetic and entropic driving forces.  In this talk, recent advances in the calculation and interpretation of the activation energy for a dynamical process will be discussed. Specifically, new approaches that enable the direct determination of the activation energy for any timescale from simulations at a single temperature will be presented. These methods open up significant new possibilities for understanding dynamics from diffusion to reorientation to chemical reaction, including in cases where a traditional Arrhenius analysis is not possible or applicable. They also enable otherwise unavailable mechanistic insight via a rigorous decomposition of the activation energy into contributions associated with the different interactions (e.g., Coulombic, Lennard-Jones) and motions present in the system.  The approach is illustrated by application to the structure and dynamics of water and small peptides.