Theoretical study of an isotope effect on rate constants for the CH3+H2→CH4+H and CD3+H2→CD3H+H reactions using variational transition state theory and the multidimensional semiclassical tunneling method

1999 ◽  
Vol 110 (22) ◽  
pp. 10830-10842 ◽  
Author(s):  
Yuzuru Kurosaki ◽  
Toshiyuki Takayanagi
Keyword(s):  
Transition State ◽  
Isotope Effect ◽  
Rate Constants ◽  
Transition State Theory ◽  
Theoretical Study ◽  
State Theory ◽  
Variational Transition State Theory ◽  
Tunneling Method ◽  
Semiclassical Tunneling ◽  
Variational Transition State

Theoretical Study on the Reaction of Et3GeCH=CH2 with Et3SiOH

2012 ◽  
Vol 549 ◽  
pp. 301-304
Author(s):  
Xin Cheng Chen ◽  
Xiao Yun Han ◽  
Wan Yong Ma ◽  
Li Gang Gai
Keyword(s):  
Quantum Chemistry ◽  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Theoretical Study ◽  
State Theory ◽  
Arrhenius Behavior ◽  
Variational Transition State Theory ◽  
Temperature Range ◽  
Variational Transition State

The reaction of Et3GeCH=CH2 + Et3SiOH → Et3SiO–Ge–Et3 + CH2=CH2 has been studied using quantum chemistry methods. Geometries of reactants, transition states, and products have been optimized respectively at the b3lyp/6-311+g(2d,2p) level. The rate constants were evaluated using canonical variational transition state theory (CVT) and canonical variational transition state theory with small-curvaturetunneling contributions (CVT/SCT) over the temperature range of 200-3500K. The CVT/SCT rate constants exhibit typical non-Arrhenius behavior, and a three-parameter rate-temperature formula has been fitted as follows: k(T)=1.43×10-38T 5.41exp(-13200/T) (in units of cm3 molecule-1s-1).

Computational study on the reaction of atomic chlorine with 1,2-dibromoethane (CH2BrCH2Br)

2013 ◽  
Vol 91 (11) ◽  
pp. 1123-1129 ◽  
Author(s):  
Ang-yang Yu
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Computational Study ◽  
Minimum Energy ◽  
State Theory ◽  
Basis Set ◽  
Stationary Points ◽  
Variational Transition State Theory ◽  
Variational Transition State

In this work, the reaction mechanism and kinetics of Cl + CH2BrCH2Br → products are theoretically investigated for the first time. The optimized geometries and frequencies of all of the stationary points and selected points along the minimum-energy path for the three hydrogen abstraction channels and two bromine abstraction channels are calculated at the BH&H-LYP level with the 6-311G** basis set and the energy profiles are further calculated at the CCSD(T) level of theory. The rate constants are evaluated using the conventional transition-state theory, the canonical variational transition-state theory, and the canonical variational transition-state theory with a small-curvature tunneling correction over the temperature range 200–1000 K. The results show that reaction channel 3 is the primary channel and the calculated rate constants are in good agreement with available experimental values. The three-parameter Arrhenius expression for the total rate constants over 200–1000 K is provided.

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