Processus élémentaires en solution: Apports et limites de la théorie du complexe activé dans le cas d'un prééquilibre rapide d'échange protonique entre réactifs

1993 ◽  
Vol 71 (3) ◽  
pp. 294-302 ◽  
Author(s):  
B. Solastiouk ◽  
A. Merlin ◽  
X. Deglise
Keyword(s):  
Aqueous Solution ◽  
Transition State ◽  
Kinetic Study ◽  
Aqueous Phase ◽  
Transition State Theory ◽  
Cyanuric Acid ◽  
State Theory ◽  
Proton Exchange ◽  
Secondary Amines ◽  
Fast Proton

The kinetic study of N-chlorination reactions in the aqueous phase of different nitrogenized molecules (secondary amines, imides, cyanuric acid, etc… ) shows that the correct chlorination mechanism has not yet been determined because fast proton exchange causes weak acido-basic behaviour of the reagents in aqueous solution. We extended this result to reagents of any charge capable of fast proton exchange. This generalization demonstrates that the indeterminate nature of the mechanism is imposed by the hypotheses of transition state theory.

Temperature dependence of rate constants for the H(D) + CH4 reaction in gas and aqueous phase: deformed Transition-State Theory study including quantum tunneling and diffusion effects

2019 ◽  
Vol 31 (2) ◽  
pp. 609-617 ◽  
Author(s):  
Flávio O. Sanches-Neto ◽  
Nayara D. Coutinho ◽  
Federico Palazzetti ◽  
Valter H. Carvalho-Silva
Keyword(s):  
Transition State ◽  
Temperature Dependence ◽  
Aqueous Phase ◽  
Rate Constants ◽  
Quantum Tunneling ◽  
Transition State Theory ◽  
State Theory ◽  
Diffusion Effects ◽  
And Diffusion

scholarly journals Theoretical and kinetic study of the reaction of C2H3 + HO2 on the C2H3O2H potential energy surface

RSC Advances ◽  
2017 ◽  
Vol 7 (71) ◽  
pp. 44809-44819 ◽  
Author(s):  
Junjiang Guo ◽  
Shiyun Tang ◽  
Ningxin Tan
Keyword(s):  
Potential Energy ◽  
Transition State ◽  
Potential Energy Surface ◽  
Kinetic Study ◽  
Master Equation ◽  
Transition State Theory ◽  
Energy Surface ◽  
State Theory ◽  
Reaction Coordinate

We systematically investigate the C2H3 + HO2 reaction combined with conventional transition state theory, variable reaction coordinate transition state theory and Rice–Ramsberger–Kassel–Marcus/master-equation theory.

Microscopic Interpretation of Arrhenius Parameters

2018 ◽  
Author(s):  
Niels Engholm Henriksen ◽  
Flemming Yssing Hansen
Keyword(s):  
Activation Energy ◽  
Transition State ◽  
Transition State Theory ◽  
Average Energy ◽  
Zero Point ◽  
State Theory ◽  
Exponential Factor ◽  
Quantum Tunnelling ◽  
Microscopic Interpretation ◽  
The Difference

This chapter reviews the microscopic interpretation of the pre-exponential factor and the activation energy in rate constant expressions of the Arrhenius form. The pre-exponential factor of apparent unimolecular reactions is, roughly, expected to be of the order of a vibrational frequency, whereas the pre-exponential factor of bimolecular reactions, roughly, is related to the number of collisions per unit time and per unit volume. The activation energy of an elementary reaction can be interpreted as the average energy of the molecules that react minus the average energy of the reactants. Specializing to conventional transition-state theory, the activation energy is related to the classical barrier height of the potential energy surface plus the difference in zero-point energies and average internal energies between the activated complex and the reactants. When quantum tunnelling is included in transition-state theory, the activation energy is reduced, compared to the interpretation given in conventional transition-state theory.

Bimolecular Reactions, Transition-State Theory

2018 ◽  
Author(s):  
Niels Engholm Henriksen ◽  
Flemming Yssing Hansen
Keyword(s):  
Transition State ◽  
Saddle Point ◽  
Transition State Theory ◽  
Classical Mechanics ◽  
Small Degree ◽  
State Theory ◽  
Reaction Coordinate ◽  
Partition Functions ◽  
Bimolecular Reactions ◽  
Activated Complex

This chapter discusses an approximate approach—transition-state theory—to the calculation of rate constants for bimolecular reactions. A reaction coordinate is identified from a normal-mode coordinate analysis of the activated complex, that is, the supermolecule on the saddle-point of the potential energy surface. Motion along this coordinate is treated by classical mechanics and recrossings of the saddle point from the product to the reactant side are neglected, leading to the result of conventional transition-state theory expressed in terms of relevant partition functions. Various alternative derivations are presented. Corrections that incorporate quantum mechanical tunnelling along the reaction coordinate are described. Tunnelling through an Eckart barrier is discussed and the approximate Wigner tunnelling correction factor is derived in the limit of a small degree of tunnelling. It concludes with applications of transition-state theory to, for example, the F + H2 reaction, and comparisons with results based on quasi-classical mechanics as well as exact quantum mechanics.

Basic Transition State Theory

1999 ◽  
pp. 18-56
Author(s):  
Margaret Robson Wright
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
State Theory

Quasiclassical Trajectory and Transition State Theory Studies of the N(4S) + H2↔ NH(X3Σ-) + H Reaction

2002 ◽  
Vol 106 (16) ◽  
pp. 4125-4136 ◽  
Author(s):  
Ronald Z. Pascual ◽  
George C. Schatz ◽  
Gÿorgÿ Lendvay ◽  
Diego Troya
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
State Theory
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