Ab initio variational transition state theory calculations for the O+NH2 hydrogen abstraction reaction on the 4A’ and 4A‘ potential energy surfaces

1995 ◽  
Vol 102 (15) ◽  
pp. 6121-6127 ◽  
Author(s):  
Xiaofeng Duan ◽  
Michael Page
Keyword(s):  
Potential Energy ◽  
Transition State ◽  
Potential Energy Surfaces ◽  
Transition State Theory ◽  
Hydrogen Abstraction ◽  
State Theory ◽  
Variational Transition State Theory ◽  
Abstraction Reaction ◽  
Energy Surfaces ◽  
Hydrogen Abstraction Reaction

AB INITIO CALCULATIONS AND KINETICS STUDY FOR THE DIRECT HYDROGEN ABSTRACTION REACTION OF HYDROGEN SELENIDE WITH HYDROGEN ATOM

2011 ◽  
Vol 10 (05) ◽  
pp. 629-639
Author(s):  
YUE ZHANG
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Hydrogen Abstraction ◽  
State Theory ◽  
Forward Rate ◽  
Variational Transition State Theory ◽  
Abstraction Reaction ◽  
Hydrogen Abstraction Reaction ◽  
Good Agreement

We present a direct ab initio dynamics study of thermal rate constants of the hydrogen abstraction reaction of H 2 Se + H → SeH + H 2. The QCISD and CCSD(T) methods were employed to optimize the geometries of stationary points and to calculate the harmonic vibrational frequencies. The split-valence 6-311 + G(d,p) and correlation-consistent cc-pVTZ basis sets big enough to describe the geometries and vibrational frequencies of the species involving in the title reaction. The energies obtained at the QCISD(T)/6-311 ++ G(3df,3pd)//QCISD/6-311 + G(d,p) level of theory is able to compare to those calculated at the CCSD(T)/6-311 ++ G(3df,3pd)//CCSD(T)/6-311 + G(d,p) level of theory. The energies of all the selected points along the minimum energy path (MEP) were refined at the QCISD(T)/6-311 ++ G(3df,3pd) level of theory. The barriers were obtained at the both QCISD(T)/6-311 ++ G(3df,3pd)//QCISD/6-311 + G(d,p) and CCSD(T)/6-311 ++ G(3df,3pd)//CCSD(T)/6-311 + G(d,p) levels of theory are in good agreement with experimental one. The forward rate constants were evaluated with both canonical variational transition state theory with small curvature tunneling correction (CVT/SCT) and improved canonical variational transition state theory with small curvature tunneling correction (ICVT/SCT) in the temperature range of 200–2500 K. The calculated forward rate constants of the reaction at the QCISD(T)/6-311 ++ G(3df,3pd)//QCISD/6-311 + G(d,p) level of theory are in good agreement with available experimental data.

Dynamics of X+CH4 (X=H,O,Cl) reactions: How reliable is transition state theory for fine-tuning potential energy surfaces?

2006 ◽  
Vol 125 (6) ◽  
pp. 064312 ◽  
Author(s):  
A. J. C. Varandas ◽  
P. J. S. B. Caridade ◽  
J. Z. H. Zhang ◽  
Q. Cui ◽  
K. L. Han
Keyword(s):  
Potential Energy ◽  
Transition State ◽  
Potential Energy Surfaces ◽  
Transition State Theory ◽  
State Theory ◽  
Fine Tuning ◽  
Energy Surfaces

scholarly journals Theoretical Kinetics Study Of The HO2 + C2H5OH Hydrogen Abstraction Reaction

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Nguyen Trong Nghia
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Hydrogen Abstraction ◽  
Branching Ratios ◽  
State Theory ◽  
Kinetics Study ◽  
Abstraction Reaction ◽  
Hydrogen Abstraction Reaction ◽  
Ho2 Radical

C2H5OH has been using as an alternative fuel for decades; HO2 also plays a pivotal role in the combustion. The kinetics and mechanism for the reaction between C2H5OH and HO2 radical has been investigated using the molecular parameters for the reactants, transition states and products predicted at the CCSD(T)//B3LYP/6-311++G(3df,2p) level of theory. There are ten pair products have been found including C2H5O + H2O2 (PR1), CH3CHOH + H2O2 (PR2), CH2CH2OH + H2O2 (PR3), CH3CH2OOOH + H (PR4), C2H5 + HOOOH (PR5), CH3CH2OOH + OH (PR6), CH3CH(OH)OOH + H (PR7), HOCH2CH2OH + H (PR8), HOOCH3 + CH2OH (PR9), and CH3 + HOOCH2OH (PR10) in which the second and third ones are the major channels. The rate constants and branching ratios for all H-abstraction reactions have been calculated using the conventional transition state theory with asymmetric Eckart tunneling corrections for the temperature ranging from 298 to 2000 K.

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