Dissociation dynamics of CH3SH at 222, 248, and 193 nm: An analog for probing nonadiabaticity in the transition state region of bimolecular reactions

1993 ◽  
Vol 98 (4) ◽  
pp. 2882-2890 ◽  
Author(s):  
E. Jensen ◽  
J. S. Keller ◽  
G. C. G. Waschewsky ◽  
J. E. Stevens ◽  
R. L. Graham ◽  
...  
Keyword(s):  
Transition State ◽  
Bimolecular Reactions ◽  
Dissociation Dynamics ◽  
State Region ◽  
193 Nm

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.

Picturing the Transition-State Region and Understanding Vibrational Enhancement for the Cl + CH4→ HCl + CH3Reaction

1996 ◽  
Vol 100 (19) ◽  
pp. 7938-7947 ◽  
Author(s):  
William R. Simpson ◽  
T. Peter Rakitzis ◽  
S. Alex Kandel ◽  
Topaz Lev-On ◽  
Richard N. Zare
Keyword(s):  
Transition State ◽  
State Region ◽  
Vibrational Enhancement

Study of the transition state region in the Cl+HCl reaction by photoelectron spectroscopy of ClHCl−

1988 ◽  
Vol 88 (2) ◽  
pp. 1463-1465 ◽  
Author(s):  
R. B. Metz ◽  
T. Kitsopoulos ◽  
A. Weaver ◽  
D. M. Neumark
Keyword(s):  
Transition State ◽  
Photoelectron Spectroscopy ◽  
State Region

Evidence for stepwise dissociation dynamics in acetone at 248 and 193 nm

1995 ◽  
Vol 102 (11) ◽  
pp. 4447-4460 ◽  
Author(s):  
Simon W. North ◽  
David A. Blank ◽  
J. Daniel Gezelter ◽  
Cheryl A. Longfellow ◽  
Yuan T. Lee
Keyword(s):  
Dissociation Dynamics ◽  
193 Nm ◽  
Stepwise Dissociation

scholarly journals Sampling the Folding Transition State Ensemble in a Tube-Like Model of Protein

10.29007/ml3c ◽  
2020 ◽  
Author(s):  
Ba Hung Nguyen ◽  
Hoang Trinh Xuan
Keyword(s):  
Free Energy ◽  
Transition State ◽  
Energy Surface ◽  
Sampling Technique ◽  
Small Region ◽  
Umbrella Sampling ◽  
Free Energy Surface ◽  
State Ensemble ◽  
State Region ◽  
Transition State Ensemble

We used the tube model with Go-like potential for native contacts to study the folding transition of a designed three-helix bundle and a designed protein G-like structure. It is shown that both proteins in this model are two-state folders with a cooperative folding transition coincided with the collapse transition. We defined the transition states as protein conformations in a small region around the saddle point on a free energy surface with the energy and the conformational root-mean-square deviation (RMSD) from the native state as the coordinates. The transition state region on the free energy surface then was sampled by using the umbrella sampling technique. We show that the transition state ensemble is broad consisting of different conformations that have different folded and unfolded elements.

scholarly journals Multiphoton dissociation dynamics of the indenyl radical at 248 nm and 193 nm

2019 ◽  
Vol 151 (17) ◽  
pp. 174303
Author(s):  
Erin N. Sullivan ◽  
Bethan Nichols ◽  
Stephen von Kugelgen ◽  
Gabriel da Silva ◽  
Daniel M. Neumark
Keyword(s):  
Dissociation Dynamics ◽  
Multiphoton Dissociation ◽  
193 Nm

Reaction path Hamiltonian for the association reactions CH3 + H and CH3 + D

1992 ◽  
Vol 70 (7) ◽  
pp. 1897-1904 ◽  
Author(s):  
David M. Wardlaw
Keyword(s):  
Transition State ◽  
Transition State Theory ◽  
Reaction Path ◽  
State Theory ◽  
Hydrogen Separation ◽  
Coupling Coefficients ◽  
Symmetry Coordinates ◽  
Different Types ◽  
State Region ◽  
Reaction Path Hamiltonian

Coupling coefficients and normal mode frequencies appearing in the reaction path Hamiltonian formulated by Miller, Handy, and Adams have been calculated for the title reactions as a function of distance along the reaction path. The calculation of the coupling coefficients requires the use of symmetry coordinates which are described herein. It is found that the carbon–hydrogen separation provides an excellent representation of the reaction path coordinate, being linearly related to it. The coupling coefficients for CH3 + H and CH3 + D are approximately the same in the region of variational transition states and do not support the suggestion that an apparent isotope anomaly in the experimentally derived rates of these reactions might be attributable to different dynamics along the reaction path. The relative magnitudes of coupling coefficients for CH3 + H are used to assess some of the usual assumptions in variational transition state theory concerning separability of different types of motion in the transition state region.

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