Variational transition state theory calculations of thermal rate coefficients for the Q(3P) + HCl reaction

Thomas C. Allison; B. Ramachandran; Jörg Senekowitsch; Donald G. Truhlar; Robert E. Wyatt

doi:10.1016/S0166-1280(98)00300-5

Variational transition state theory calculations of thermal rate coefficients for the Q(³P) + HCl reaction

Thomas C. Allison, B. Ramachandran, Jörg Senekowitsch, Donald G. Truhlar, Robert E. Wyatt

Chemistry (Twin Cities)

Research output: Contribution to journal › Article › peer-review

16 Scopus citations

Abstract

Variational Transition State Theory (VTST) calculations of the thermal rate coefficients of the reaction of O(³P) with HCl are presented. Four potential surfaces for the ³A″ state are studied, three of them due to Ramachandran, Senekowitsch and Wyatt (RSW), based on fits to scaled MR-CISD + Q energies, and the fourth due to Koizumi, Schatz and Gordon (KSG), based on scaled MP2/6-31G(d,p) energies. Using the program POLYRATE, version 7.3, the rate coefficients are calculated using Improved Canonical Variational Theory (ICVT) with the microcanonical Optimized Multidimensional Tunneling (μOMT) approximation over the temperature range 200-1500K. These results are compared to available experimental data, which lie in the range 293-1486K. It is found that the RSW surfaces yield thermal rate coefficients that are in reasonable agreement with experimental data over this range, and in very good agreement for T > 500K, while those computed on the KSG surface are somewhat higher. These comparisons indicate that one of the RSW surfaces may establish an upper limit for the correct reaction barrier for this reaction, while the KSG surface could provide a lower limit.

Original language	English (US)
Pages (from-to)	307-314
Number of pages	8
Journal	Journal of Molecular Structure: THEOCHEM
Volume	454
Issue number	2-3
DOIs	https://doi.org/10.1016/S0166-1280(98)00300-5
State	Published - Nov 28 1998

Bibliographical note

Funding Information:
This research is supported by a grant to B.R. from the Louisiana Education Quality Support Fund, under contract no. LEQSF (1994-97)-RD-A-18. R.E.W. acknowledges support from the National Science Foundation and the Welch Foundation, and D.G.T. acknowledges support from the US Department of Energy, Office of Basic Energy Sciences. We are grateful to Drs Javier Aoiz and Juan E. Verdasco for sending us a subroutine to evaluate the KSG potential surface and its derivatives, and to Dr B. Poirier for sending us the quantal rate coefficients from Refs [45, 46] .

Keywords

Potential surfaces
Rate coefficients
Reaction barriers
Transition state theory

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title = "Variational transition state theory calculations of thermal rate coefficients for the Q(3P) + HCl reaction",

abstract = "Variational Transition State Theory (VTST) calculations of the thermal rate coefficients of the reaction of O(3P) with HCl are presented. Four potential surfaces for the 3A″ state are studied, three of them due to Ramachandran, Senekowitsch and Wyatt (RSW), based on fits to scaled MR-CISD + Q energies, and the fourth due to Koizumi, Schatz and Gordon (KSG), based on scaled MP2/6-31G(d,p) energies. Using the program POLYRATE, version 7.3, the rate coefficients are calculated using Improved Canonical Variational Theory (ICVT) with the microcanonical Optimized Multidimensional Tunneling (μOMT) approximation over the temperature range 200-1500K. These results are compared to available experimental data, which lie in the range 293-1486K. It is found that the RSW surfaces yield thermal rate coefficients that are in reasonable agreement with experimental data over this range, and in very good agreement for T > 500K, while those computed on the KSG surface are somewhat higher. These comparisons indicate that one of the RSW surfaces may establish an upper limit for the correct reaction barrier for this reaction, while the KSG surface could provide a lower limit.",

keywords = "Potential surfaces, Rate coefficients, Reaction barriers, Transition state theory",

author = "Allison, {Thomas C.} and B. Ramachandran and J{\"o}rg Senekowitsch and Truhlar, {Donald G.} and Wyatt, {Robert E.}",

note = "Funding Information: This research is supported by a grant to B.R. from the Louisiana Education Quality Support Fund, under contract no. LEQSF (1994-97)-RD-A-18. R.E.W. acknowledges support from the National Science Foundation and the Welch Foundation, and D.G.T. acknowledges support from the US Department of Energy, Office of Basic Energy Sciences. We are grateful to Drs Javier Aoiz and Juan E. Verdasco for sending us a subroutine to evaluate the KSG potential surface and its derivatives, and to Dr B. Poirier for sending us the quantal rate coefficients from Refs [45, 46] . ",

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T1 - Variational transition state theory calculations of thermal rate coefficients for the Q(3P) + HCl reaction

AU - Allison, Thomas C.

AU - Ramachandran, B.

AU - Senekowitsch, Jörg

AU - Truhlar, Donald G.

AU - Wyatt, Robert E.

N1 - Funding Information: This research is supported by a grant to B.R. from the Louisiana Education Quality Support Fund, under contract no. LEQSF (1994-97)-RD-A-18. R.E.W. acknowledges support from the National Science Foundation and the Welch Foundation, and D.G.T. acknowledges support from the US Department of Energy, Office of Basic Energy Sciences. We are grateful to Drs Javier Aoiz and Juan E. Verdasco for sending us a subroutine to evaluate the KSG potential surface and its derivatives, and to Dr B. Poirier for sending us the quantal rate coefficients from Refs [45, 46] .

PY - 1998/11/28

Y1 - 1998/11/28

N2 - Variational Transition State Theory (VTST) calculations of the thermal rate coefficients of the reaction of O(3P) with HCl are presented. Four potential surfaces for the 3A″ state are studied, three of them due to Ramachandran, Senekowitsch and Wyatt (RSW), based on fits to scaled MR-CISD + Q energies, and the fourth due to Koizumi, Schatz and Gordon (KSG), based on scaled MP2/6-31G(d,p) energies. Using the program POLYRATE, version 7.3, the rate coefficients are calculated using Improved Canonical Variational Theory (ICVT) with the microcanonical Optimized Multidimensional Tunneling (μOMT) approximation over the temperature range 200-1500K. These results are compared to available experimental data, which lie in the range 293-1486K. It is found that the RSW surfaces yield thermal rate coefficients that are in reasonable agreement with experimental data over this range, and in very good agreement for T > 500K, while those computed on the KSG surface are somewhat higher. These comparisons indicate that one of the RSW surfaces may establish an upper limit for the correct reaction barrier for this reaction, while the KSG surface could provide a lower limit.

AB - Variational Transition State Theory (VTST) calculations of the thermal rate coefficients of the reaction of O(3P) with HCl are presented. Four potential surfaces for the 3A″ state are studied, three of them due to Ramachandran, Senekowitsch and Wyatt (RSW), based on fits to scaled MR-CISD + Q energies, and the fourth due to Koizumi, Schatz and Gordon (KSG), based on scaled MP2/6-31G(d,p) energies. Using the program POLYRATE, version 7.3, the rate coefficients are calculated using Improved Canonical Variational Theory (ICVT) with the microcanonical Optimized Multidimensional Tunneling (μOMT) approximation over the temperature range 200-1500K. These results are compared to available experimental data, which lie in the range 293-1486K. It is found that the RSW surfaces yield thermal rate coefficients that are in reasonable agreement with experimental data over this range, and in very good agreement for T > 500K, while those computed on the KSG surface are somewhat higher. These comparisons indicate that one of the RSW surfaces may establish an upper limit for the correct reaction barrier for this reaction, while the KSG surface could provide a lower limit.

KW - Potential surfaces

KW - Rate coefficients

KW - Reaction barriers

KW - Transition state theory

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JO - Journal of Molecular Structure: THEOCHEM

JF - Journal of Molecular Structure: THEOCHEM

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