Deformed transition-state theory: Deviation from Arrhenius behavior and application to bimolecular hydrogen transfer reaction rates in the tunneling regime

2016 ◽  
Vol 38 (3) ◽  
pp. 178-188 ◽  
Author(s):  
Valter H. Carvalho-Silva ◽  
Vincenzo Aquilanti ◽  
Heibbe C. B. de Oliveira ◽  
Kleber C. Mundim
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Reaction Rates ◽  
State Theory ◽  
Arrhenius Behavior ◽  
Hydrogen Transfer Reaction

Reaction rates of BrH+Cl→Br+HCl using semiclassical transition state theory

1994 ◽  
Vol 223 (5-6) ◽  
pp. 459-464 ◽  
Author(s):  
Michael J. Cohen ◽  
Andrew Willetts ◽  
Nicholas C. Handy
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
Reaction Rates ◽  
State Theory

Étude théorique des réactions d'abstraction d'hydrogène , avec R, X≡H, CH3, NH2,OH et F

1985 ◽  
Vol 63 (7) ◽  
pp. 1447-1456 ◽  
Author(s):  
Georges Leroy ◽  
Michel Sana ◽  
Anne Tinant
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Hydrogen Abstraction ◽  
State Theory ◽  
Arrhenius Behavior ◽  
Activation Barriers ◽  
Empirical Procedure ◽  
Semi Empirical ◽  
Theory And Experiment

Hydrogen abstraction reactions [Formula: see text] with R, X≡H, CH3, NH2,OH, and F have been studied at the abinitio 6-31G – UHF level. However, energetic properties were computed at the CI level. Rate constants and Arrhenius parameters have been obtained using the transition state theory formalism with Eckart's tunneling correction. The discrepancy between theoretical and experimental results led us to elaborate a semi-empirical procedure to calculate activation barriers, in which the bonds R—H and X—H are represented by Morse curves. Thus, the agreement between theory and experiment is much better. Moreover, the results obtained by this procedure demonstrate the non-Arrhenius behavior of all the reactions under consideration and allow us to rationalize a large number of experimental facts.

scholarly journals Hot atom chemistry: oxygen at stepped platinum surfaces

2021 ◽  
Author(s):  
Axel Gross
Keyword(s):  
Transition State ◽  
Thermal Equilibrium ◽  
Transition State Theory ◽  
Reaction Rates ◽  
State Theory ◽  
Ab Initio Molecular Dynamics ◽  
Quasi Equilibrium ◽  
Platinum Surfaces ◽  
Dynamics Simulations ◽  
Atom Chemistry

It is a paradigm in chemistry that chemical reaction are mainly governed by thermodynamics. Within this assumption, reaction rates can be derived from transition state theory which requires a quasi-equilibrium between reactants and activated transition state complexes that is achieved through friction. However, to reach thermal equilibrium through friction takes some time. Here we show, based on ab initio molecular dynamics simulations of the interaction of molecular oxygen with stepped Pt surfaces, that chemical reactions in heterogeneous catalysis can occur in a non-equilibrium fashion when the excess kinetic energy upon entering the potential well of a reaction intermediate is large enough.

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