On why some low-energy decomposition pathways of simple ketone molecular ions do not give rise to metastable peaks. A reappraisal

1986 ◽  
Vol 64 (10) ◽  
pp. 1957-1959 ◽  
Author(s):  
Peter J. Derrick ◽  
Steen Hammerum
Keyword(s):  
Rate Constants ◽  
Molecular Ions ◽  
Equilibrium Theory ◽  
Low Energy ◽  
Quasi Equilibrium ◽  
Energy Decomposition ◽  
Minimum Rate ◽  
Process Loss ◽  
Energy Reaction

The concept of minimum rate constants, k(E)min, for unimolecular decompositions does not, according to the quasi equilibrium theory (QET), provide a rationalisation of the occurrence of the higher energy reaction, loss of methyl, rather than the more favorable process, loss of methane, from metastable butanone and 3-methylbutanone molecular ions.

Quasi-Equilibrium Theory of Ionic Fragmentation: Further Considerations

1972 ◽  
Vol 27 (4) ◽  
pp. 553-561 ◽  
Author(s):  
Cornelius E. Klots
Keyword(s):  
Rate Constants ◽  
Equilibrium Theory ◽  
Quasi Equilibrium ◽  
Interesting Possibility ◽  
Ionic Fragmentation

Abstract A recent reformulation of quasi-equilibrium theory is extended to several additional classes of ionic decompositions. Formulae for calculating average translational and rotational energies of the fragments are presented, and kinematic corrections to the formulas are introduced. Illustrative calculations are compared with experiment, and the interesting possibility of maxima in rate constants is noted.

Low-Energy Reaction Rate Constants for the Ni+-Assisted Decomposition of Acetaldehyde: Observation of C−H and C−C Activation

2010 ◽  
Vol 114 (4) ◽  
pp. 1783-1789 ◽  
Author(s):  
S. Jason Dee ◽  
Vanessa A. Castleberry ◽  
Otsmar J. Villarroel ◽  
Ivanna E. Laboren ◽  
Darrin J. Bellert
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Low Energy ◽  
Reaction Rate Constants ◽  
Assisted Decomposition ◽  
Energy Reaction

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.

Fragmentations des cétones aliphatiques métastables. II. Compétition entre éliminations de radicaux hydrocarbonés et d'alcanes.

1982 ◽  
Vol 60 (16) ◽  
pp. 2107-2112 ◽  
Author(s):  
Guy Bouchoux ◽  
Yannik Hoppilliard
Keyword(s):  
Molecular Ions ◽  
Low Energy ◽  
Final States ◽  
Energy Channel ◽  
Aliphatic Ketones ◽  
Thermochemical Stability

The fragmentation of the metas table molecular ions of six aliphatic ketones is studied. The ion fragment abundances [M – R•] and [M–RH] (R• being a lateral radical) can be predicted from the thermochemical stability of the corresponding final states. Exceptions to this behavior are found for metastable molecular ions of methylethylketone and methylisopropylketone where it is demonstrated that the lifetime of these ions is too short to permit significant decompositions via the low energy channel after 10−5 s.

scholarly journals Sparse + low-energy decomposition for viscous conservation laws

2015 ◽  
Vol 288 ◽  
pp. 150-166 ◽  
Author(s):  
Thomas Y. Hou ◽  
Qin Li ◽  
Hayden Schaeffer
Keyword(s):  
Conservation Laws ◽  
Low Energy ◽  
Energy Decomposition ◽  
Viscous Conservation Laws

Improved Rate Expression in the Quasi‐Equilibrium Theory of Mass Spectra

1962 ◽  
Vol 37 (6) ◽  
pp. 1276-1283 ◽  
Author(s):  
Marvin Vestal ◽  
Austin L. Wahrhaftig ◽  
William H. Johnston
Keyword(s):  
Mass Spectra ◽  
Equilibrium Theory ◽  
Quasi Equilibrium ◽  
Rate Expression

scholarly journals Low-energy collisions with atomic and molecular ions in a photocathode electron target

2009 ◽  
Vol 194 (1) ◽  
pp. 012024 ◽  
Author(s):  
A Wolf ◽  
D A Orlov ◽  
C Krantz ◽  
M Lestinsky ◽  
A Shornikov ◽  
...  
Keyword(s):  
Molecular Ions ◽  
Low Energy ◽  
Electron Target
Sign in / Sign up

Export Citation Format

Share Document