Dynamics Calculations Based on Ab Initio Potential Energy Surfaces

We present a new potential energy surface (called G3) for the chemical reaction Cl + H2 → HCl + H. The new surface is based on a previous potential surface called GQQ, and it incorporates an improved bending potential that is fit to the results of ab initio electronic structure calculations. Calculations based on variational transition state theory with semiclassical transmission coefficients corresponding to an optimized multidimensional tunneling treatment (VTST/OMT, in particular improved canonical variational theory with least-action ground-state transmission coefficients) are carried out for nine different isotopomeric versions of the abstraction reaction and six different isotopomeric versions of the exchange reaction involving the H, D, and T isotopes of hydrogen, and the new surface is tested by comparing these calculations to available experimental data. The theoretical data are also used to investigate the equilibrium constant and the branching ratio for the reverse reaction, and calculations of these quantities are compared to the available experimental and theoretical data. Disciplines Chemistry CommentsReprinted (adapted) ReceiVed: March 13, 1996; In Final Form: May 15, 1996 X We present a new potential energy surface (called G3) for the chemical reaction Cl + H 2 f HCl + H. The new surface is based on a previous potential surface called GQQ, and it incorporates an improved bending potential that is fit to the results of ab initio electronic structure calculations. Calculations based on variational transition state theory with semiclassical transmission coefficients corresponding to an optimized multidimensional tunneling treatment (VTST/OMT, in particular improved canonical variational theory with leastaction ground-state transmission coefficients) are carried out for nine different isotopomeric versions of the abstraction reaction and six different isotopomeric versions of the exchange reaction involving the H, D, and T isotopes of hydrogen, and the new surface is tested by comparing these calculations to available experimental data. The theoretical data are also used to investigate the equilibrium constant and the branching ratio for the reverse reaction, and calculations of these quantities are compared to the available experimental and theoretical data.

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“…The reactions of a chlorine atom with a hydrogen molecule have been the subject a great deal of experimental − and theoretical − …”

Section: Introductionmentioning

confidence: 99%

An Improved Potential Energy Surface for the H₂Cl System and Its Use for Calculations of Rate Coefficients and Kinetic Isotope Effects

et al. 1996

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The Interface Between Electronic Structure Theory and Reaction Dynamics by Reaction Path Methods

Collins

1996

Advances in Chemical Physics

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Reaction rates for O + HD → OH + D and O + HD → OD + H

Garrett

Truhlar

1987

Int J of Quantum Chemistry

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We have calcuirted reaction ntu for the reactions 0 + HD -. OH + D and 0 + DH + OD + H ticiarrr with aa ab inicio potmtbl energy surfrc. The kinetic isotopeeffects are in goad ageanent with f a v i b d m u U y excited rcmants are dro pcesciW rad comprrrd with thosc f o r b isotopipmdiued u) occur by muding ai exmdcdconfigundons. i.e.. to iniriueeprty on the reaction Pafh and to avoid Ibe W e pin1 mgioat. 'hneling also dominates the low and mom temperature reactions for excited vibrrtioari states. but in thu cases th results are not u sensitive to du nanuc of the pth. -' mcchrnisw dominrte for both thmnd ud excitcbvibmtiod state reactions for T > 601) K. For the excited-state & fwith initial vibrathmi quantum nurnba n > 0) a transition state switch occurs for T > lo00 K for the 0 + HD(n = 1)-00 + H case and for I > 15OO K for the 0 + DH(n = I) OD + H ractioa. and this may be a g e d phewnwnon for excited-state d o n s 0 1987 John Wiley & Soas. Inc.

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Dynamics Calculations Based on Ab Initio Potential Energy Surfaces

Cited by 6 publications

References 139 publications

An Improved Potential Energy Surface for the H₂Cl System and Its Use for Calculations of Rate Coefficients and Kinetic Isotope Effects

An Improved Potential Energy Surface for the H₂Cl System and Its Use for Calculations of Rate Coefficients and Kinetic Isotope Effects

The Interface Between Electronic Structure Theory and Reaction Dynamics by Reaction Path Methods

Reaction rates for O + HD → OH + D and O + HD → OD + H

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Dynamics Calculations Based on Ab Initio Potential Energy Surfaces

Cited by 6 publications

References 139 publications

An Improved Potential Energy Surface for the H2Cl System and Its Use for Calculations of Rate Coefficients and Kinetic Isotope Effects

An Improved Potential Energy Surface for the H2Cl System and Its Use for Calculations of Rate Coefficients and Kinetic Isotope Effects

The Interface Between Electronic Structure Theory and Reaction Dynamics by Reaction Path Methods

Reaction rates for O + HD → OH + D and O + HD → OD + H

Contact Info

Product

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An Improved Potential Energy Surface for the H₂Cl System and Its Use for Calculations of Rate Coefficients and Kinetic Isotope Effects

An Improved Potential Energy Surface for the H₂Cl System and Its Use for Calculations of Rate Coefficients and Kinetic Isotope Effects