Mode specificity in the model unimolecular reaction H-C-C .fwdarw. H + C:C

1986 ◽  
Vol 90 (16) ◽  
pp. 3517-3524 ◽  
Author(s):  
Kandadai N. Swamy ◽  
William L. Hase ◽  
Bruce C. Garrett ◽  
C. William McCurdy ◽  
J. F. McNutt
Keyword(s):  
Unimolecular Reaction ◽  
Mode Specificity

scholarly journals On the Question of Mode-Specificity in Unimolecular Reaction Dynamics

1983 ◽  
Vol 2 (5-6) ◽  
pp. 243-252 ◽  
Author(s):  
William H. Miller
Keyword(s):  
Transition State ◽  
Coupled Oscillators ◽  
Laser Excitation ◽  
Model Problem ◽  
Significant Degree ◽  
Decay Rates ◽  
Unimolecular Reaction ◽  
Unimolecular Decomposition ◽  
Planar Transition ◽  
Mode Specificity

Unimolecular decomposition following state-specific laser excitation is considered. If the transition state for the unimolecular reaction possesses any geometrical symmetry, then it is shown that this can lead to mode-specificity in the decay rates (i.e., different states with essentially the same total energy and angular momentum react at significantly different rates). This is illustrated for a model problem of two coupled oscillators (the Henon–Heiles potential) and also for the unimolecular dissociation of formaldehyde, H2CO→H2+CO, which has a planar transition state. Dynamical calculations indicate that there may also be a significant degree of mode-specificity for the formaldehyde reaction beyond that due to symmetry.

Computational Study on the Kinetics and Mechanisms of Unimolecular Reactions of (Z)-(Z)-N-(λ5-phosphanylidene) Formohydrazonic Formic Anhydride: Intramolecular aza-Wittig Reaction in Competition with Mumm Rearrangement

2020 ◽  
Vol 17 (11) ◽  
pp. 884-889
Author(s):  
Somayeh Mirdoraghi ◽  
Hamed Douroudgari ◽  
Farideh Piri ◽  
Morteza Vahedpour
Keyword(s):  
Rate Constants ◽  
Density Functional ◽  
Wittig Reaction ◽  
Computational Study ◽  
Single Step ◽  
Low Energy ◽  
Coupled Cluster ◽  
Unimolecular Reaction ◽  
Single Step Reaction ◽  
Good Agreement

For (Z)-(Z)-N-(λ5-phosphanylidene) formohydrazonic formic anhydride, Aza-Wittig reaction and Mumm rearrangement are studied using both density functional and coupled cluster theories. For this purpose, two different products starting from one substrate are considered that are competing with each other. The obtained products, P1 and P2, are thermodynamically favorable. The product of the aza-Wittig reaction, P1, is more stable than the product of Mumm rearrangement (P2). For the mentioned products, just one reliable pathway is separately proposed based on unimolecular reaction. Therefore, the rate constants based on RRKM theory in 300-600 K temperature range are calculated. Results show that the P1 generation pathway is a suitable path due to low energy barriers than the path P2. The first path has three steps with three transition states, TS1, TS2, and TS3. The P2 production path is a single-step reaction. In CCSD level, the computed barrier energies are 14.55, 2.196, and 10.67 kcal/mol for Aza-Wittig reaction and 42.41 kcal/mol for Mumm rearrangement in comparison with the corresponding complexes or reactants. For final products, the results of the computational study are in a good agreement with experimental predictions.

Theoretical studies of mode specificity in the dissociation of overtone-excited hydrogen peroxide

1988 ◽  
Vol 152 (4-5) ◽  
pp. 405-408 ◽  
Author(s):  
T. Uzer ◽  
Brian D. Macdonald ◽  
Yuhua Guan ◽  
D.L. Thompson
Keyword(s):  
Hydrogen Peroxide ◽  
Theoretical Studies ◽  
Mode Specificity

Effect of Microsolvation on the Mode Specificity of OH • (H 2 O) + HCl Reaction

2021 ◽  
Author(s):  
Subhasish Mallick ◽  
Pradeep Kumar
Keyword(s):  
Dynamics Simulation ◽  
Direct Dynamics ◽  
Mode Specificity

The present study investigates the mode specificity in microsolvated OH • (H 2 O) + HCl re- action using on-the-fly direct dynamics simulation. To the best of our knowledge, this...

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