Atmospheric Reaction Rate Constants and Kinetic Isotope Effects Computed Using the HEAT Protocol and Semi-Classical Transition State Theory

2017 ◽  
pp. 403-492 ◽  
Author(s):  
Thanh Lam Nguyen ◽  
John R. Barker ◽  
John F. Stanton
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Reaction Rate ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
State Theory ◽  
Reaction Rate Constants ◽  
Kinetic Isotope ◽  
Atmospheric Reaction

A THEORETICAL STUDY FOR H2 + CN ↔ HCN + H REACTION AND ITS KINETIC ISOTOPE EFFECTS WITH VARIATIONAL TRANSITION STATE THEORY

2006 ◽  
Vol 05 (04) ◽  
pp. 769-777 ◽  
Author(s):  
LI-PING JU ◽  
KE-LI HAN ◽  
JOHN Z. H. ZHANG
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
State Theory ◽  
Variational Transition State Theory ◽  
Kinetic Isotope ◽  
Theoretical Predictions ◽  
Variational Transition State

We present variational transition state theory (VTST) calculations for the H 2 + CN → HCN + H (R1) and D 2 + CN → DCN + D (R2) reactions and their reverses based on a global many-body expansion potential energy surface (PES) for ground-state H 2 CN (ter Horst MA, Schatz GC, Harding LB, J Chem Phys105:558, 1996). It is found that the tunneling effects are negligible over the 200–2000 K temperature range and non-negligible over 100–200 K for R1 and R2 reactions. The C–N bond acts almost as a spectator for both reactions. The present VTST rate constants are in good agreement with the available experimental results and the previous theoretical predictions for R1 and R2 reactions except for the overestimation of rate constants by VTST at lower temperatures that may be caused by recrossing effect. Additionally, the kinetic isotope effects are important for the forward R1 and R2 reactions, but not for the reverses of R1 and R2.

Isotope effects in solution: contrasts between muonium and hydrogen in reactions with acetone

1990 ◽  
Vol 68 (10) ◽  
pp. 1719-1724 ◽  
Author(s):  
David C. Walker
Keyword(s):  
Free Radicals ◽  
Physical Properties ◽  
Rate Constants ◽  
Nuclear Physics ◽  
Reaction Rate ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Reaction Rate Constants ◽  
Thiyl Radicals ◽  
Kinetic Isotope

Munonium atoms are hydrogen isotopes with positive muons rather than protons, deuterons, or tritons as nuclei. Thus, they have one ninth the mass of 1H, and microsecond lifetimes. By using nuclear physics counting techniques, muonium can be studied in a wide variety of media and its chemical and physical properties used to appraise hydrogen. Results are described for the interaction of muonium with acetone, showing two types of kinetic isotope effects, formation of free radicals, evidence for intermolecular "muonium bonding", and micelle-induced enhancements of reaction rate constants. Keywords: isotope effects, muonium atoms, muonium bonding, thiyl radicals, micelles.

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