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Title: Estimating Arrhenius parameters using temperature programmed molecular dynamics

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.4958834· OSTI ID:22675936
;  [1]
  1. Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India)

Kinetic rates at different temperatures and the associated Arrhenius parameters, whenever Arrhenius law is obeyed, are efficiently estimated by applying maximum likelihood analysis to waiting times collected using the temperature programmed molecular dynamics method. When transitions involving many activated pathways are available in the dataset, their rates may be calculated using the same collection of waiting times. Arrhenius behaviour is ascertained by comparing rates at the sampled temperatures with ones from the Arrhenius expression. Three prototype systems with corrugated energy landscapes, namely, solvated alanine dipeptide, diffusion at the metal-solvent interphase, and lithium diffusion in silicon, are studied to highlight various aspects of the method. The method becomes particularly appealing when the Arrhenius parameters can be used to find rates at low temperatures where transitions are rare. Systematic coarse-graining of states can further extend the time scales accessible to the method. Good estimates for the rate parameters are obtained with 500-1000 waiting times.

OSTI ID:
22675936
Journal Information:
Journal of Chemical Physics, Vol. 145, Issue 3; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
Country of Publication:
United States
Language:
English