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Title: Reaction mechanism and reaction coordinates from the viewpoint of energy flow

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.4943581· OSTI ID:22660794
;  [1]
  1. Department of Bioengineering, The University of Illinois at Chicago, 851 South Morgan Street, Chicago, Illinois 60607 (United States)

Reaction coordinates are of central importance for correct understanding of reaction dynamics in complex systems, but their counter-intuitive nature made it a daunting challenge to identify them. Starting from an energetic view of a reaction process as stochastic energy flows biased towards preferred channels, which we deemed the reaction coordinates, we developed a rigorous scheme for decomposing energy changes of a system, both potential and kinetic, into pairwise components. The pairwise energy flows between different coordinates provide a concrete statistical mechanical language for depicting reaction mechanisms. Application of this scheme to the C{sub 7eq} → C{sub 7ax} transition of the alanine dipeptide in vacuum revealed novel and intriguing mechanisms that eluded previous investigations of this well studied prototype system for biomolecular conformational dynamics. Using a cost function developed from the energy decomposition components by proper averaging over the transition path ensemble, we were able to identify signatures of the reaction coordinates of this system without requiring any input from human intuition.

OSTI ID:
22660794
Journal Information:
Journal of Chemical Physics, Vol. 144, Issue 11; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
Country of Publication:
United States
Language:
English