Tunnelling Corrections for Unsymmetrical Eckart Potential Energy Barriers

Johnston, Herrick L.; Heicklen, Julian

doi:10.1021/j100809a040

Cited by 480 publications

(346 citation statements)

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“…For the Eckart potential, frequently used to estimate the tunneling probability of the reaction, 68 the transmission probability as a function of energy E is potential is written for an exoergic reaction, i.e., V 1 ഛ V 2 , and * is the absolute value of the imaginary frequency. The GAUSSIAN 98 program supports the intrinsic reaction coordinate ͑IRC͒ calculation for the MP2 and DFT methods, but not for the CC method.…”

Section: Appendix B: the Tunneling Probability For An Eckart Barriermentioning

confidence: 99%

On the theory of the CO+OH reaction, including H and C kinetic isotope effects

Chen

Marcus

2005

The Journal of Chemical Physics

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The effect of pressure, temperature, H / D isotopes, and C isotopes on the kinetics of the OH + CO reaction are investigated using Rice-Ramsperger-Kassel-Marcus theory. Pressure effects are treated with a step-ladder plus steady-state model and tunneling effects are included. New features include a treatment of the C isotope effect and a proposed nonstatistical effect in the reaction. The latter was prompted by existing kinetic results and molecular-beam data of Simons and co-workers ͓J. Phys. Chem. A 102, 9559 ͑1998͒; J. Chem. Phys. 112, 4557 ͑2000͒; 113, 3173 ͑2000͔͒ on incomplete intramolecular energy transfer to the highest vibrational frequency mode in HOCO * . In treating the many kinetic properties two small customary vertical adjustments of the barriers of the two transition states were made. The resulting calculations show reasonable agreement with the experimental data on ͑1͒ the pressure and temperature dependence of the H / D effect, ͑2͒ the pressure-dependent 12 C/ 13 C isotope effect, ͑3͒ the strong non-Arrhenius behavior observed at low temperatures, ͑4͒ the high-temperature data, and ͑5͒ the pressure dependence of rate constants in various bath gases. The kinetic carbon isotopic effect is usually less than 10 per mil. A striking consequence of the nonstatistical assumption is the removal of a major discrepancy in a plot of the k OH+CO / k OD+CO ratio versus pressure. A prediction is made for the temperature dependence of the OD+ CO reaction in the low-pressure limit at low temperatures.

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Section: Appendix B: the Tunneling Probability For An Eckart Barriermentioning

confidence: 99%

On the theory of the CO+OH reaction, including H and C kinetic isotope effects

Chen

Marcus

2005

The Journal of Chemical Physics

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“…K depends on E and three other parameters which are determined by the shape of the barrier and an effective mass for the system. Johnston and Heicklen [3] …”

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A Method of Calculating Tunneling Corrections for Eckart Potential Barriers

Brown¹

1981

J. RES. NATL. BUR. STAN.

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“…The geometries, vibrational frequencies and energies of the stable species and the transition state in R3 were obtained using the methods described in Section 2.1. An additional Eckart tunneling correction [7,20] was included in the computations due to the high value of the imaginary frequency (1695 cm −1 ) of the tight transition state. For the chosen range of the temperatures that reaction R3 was fitted to, the correction term ranges from a factor of 3 to a factor of 1.06.…”

Section: Rate Constant Estimationsmentioning

confidence: 99%

Ab initio Variational Transition State Theory and Master Equation Study of the Reaction (OH)₃SiOCH₂ + CH₃ ⇌ (OH)₃SiOC₂H₅

Nurkowski

Klippenstein

Georgievskii

et al. 2015

Zeitschrift Für Physikalische Chemie

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Abstract:In this paper we use variable reaction coordinate variational transition state theory (VRC-TST) to calculate the reaction rate constants for the two reactions, R1: (OH) 3 SiOCH 2 + CH 3 (OH) 3 SiOC 2 H 5 , and R2: CH 2 OH + CH 3 C 2 H 5 OH. The first reaction is an important channel during the thermal decomposition of tetraethoxysilane (TEOS), and its rate coefficient is the main focus of this work. The second reaction is analogous to the first and is used as a basis for comparison. The interaction energies are obtained on-the-fly at the CASPT2(2e,2o)/cc-pVDZ level of theory. A one-dimensional correction to the sampled energies was introduced to account for the energetic effects of geometry relaxation along the reaction path. The computed, high-pressure rate coefficients were A comparison of the computed rates with experimental data shows good agreement and an improvement over previous results. The pressure dependency of the reaction R1 is explored by solving a master equation using helium as a bath gas. The results obtained show that the reaction is only weakly pressure dependent

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Tunnelling Corrections for Unsymmetrical Eckart Potential Energy Barriers

Cited by 480 publications

References 0 publications

On the theory of the CO+OH reaction, including H and C kinetic isotope effects

On the theory of the CO+OH reaction, including H and C kinetic isotope effects

A Method of Calculating Tunneling Corrections for Eckart Potential Barriers

Ab initio Variational Transition State Theory and Master Equation Study of the Reaction (OH)₃SiOCH₂ + CH₃ ⇌ (OH)₃SiOC₂H₅

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Tunnelling Corrections for Unsymmetrical Eckart Potential Energy Barriers

Cited by 480 publications

References 0 publications

On the theory of the CO+OH reaction, including H and C kinetic isotope effects

On the theory of the CO+OH reaction, including H and C kinetic isotope effects

A Method of Calculating Tunneling Corrections for Eckart Potential Barriers

Ab initio Variational Transition State Theory and Master Equation Study of the Reaction (OH)3SiOCH2 + CH3 ⇌ (OH)3SiOC2H5

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Ab initio Variational Transition State Theory and Master Equation Study of the Reaction (OH)₃SiOCH₂ + CH₃ ⇌ (OH)₃SiOC₂H₅