POLYRATE 4: A new version of a computer program for the calculation of chemical reaction rates for polyatomics

Lu, Da Hong; Truong, Thanh N.; Melissas, Vasilios S.; Lynch, Gillian C.; Liu, Yi Ping; Garrett, Bruce C.; Steckler, Rozeanne; Isaacson, Alan D.; Sachchida, N.; Hancock, Gene C.; Lauderdale, Jack G.; Joseph, Tomi; Truhlar, Donald G.

doi:10.1016/0010-4655(92)90012-n

Cited by 543 publications

(256 citation statements)

References 54 publications

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“…93 In many respects, this theory is similar to TST with a transmission coefficient based on large-curvature tunneling. 147,236,[260][261][262][346][347][348][349][350][351][352][353] In both cases, the TST rate constant is multiplied by a factor that reflects the "interplay between donor-acceptor configuration and nuclear tunneling". Their general expression for the transition probability takes account of all possible paths averaged over energy 305,307 and in this respect is similar to the large-curvature tunneling coefficient that involves, 260,347,[351][352][353][354] for each energy, a convolution of the probability of a given nuclear configuration and the tunneling probability at that configuration, followed by a Boltzmann average over energies.…”

Section: Modelsmentioning

confidence: 99%

“…The correct way to account for the probability of reaching the transition state quasiclassically is to calculate a quasiclassical free energy of activation (see section 5). A correct way to account for the extra rate enhancement due to systems that do not reach the transition state quasiclassically but nevertheless react by tunneling through this dividing surface is by performing a Boltzmann average over the distribution of tunneling paths weighted by their tunneling probability, as is done in the more complete approaches 260,305,307,347,351 mentioned above as well as in variational transition state theory with a multidimensional transmission coefficient (section 5).…”

Section: Modelsmentioning

confidence: 99%

“…The product of the Gaussian overlap and the Boltzmann factor is integrated over a range of the gating coordinate. The average of a tunneling factor depending on the donor-acceptor distance (or, in quantum language, on the population of excited states of a promoting mode), weighted by the probability of the system being at that distance, occurs in more generality in the largetunneling model; 260,261,347,[351][352][353][354] both theories involve deuterium tunneling over a shorter distance than protium in thermally averaged systems, as do one-dimensional tunneling models. Although the large-curvature tunneling model does not use the Franck-Condon language (which is more appropriate for spectroscopy and electron transfer, where there is a separation of time scales), a Franck-Condon process may be used as a way to visualize the tunneling event, if desired.…”

Section: Modelsmentioning

confidence: 99%

“…259 This contrast was apparently first made by Marcus, 57 who also presented seminal discussions 57,258,358,359 of corner-cutting tunneling. The small-curvature tunneling 259,351,354,375 (SCT) and large-curvature tunneling 260,347,[351][352][353][354] (LCT) approximations are formalisms for calculating corner-cutting tunneling in general polyatomic systems with full atomic detail and without separate assumptions as to which mode or modes are promoting modes. The formalism determines this from the potential energy surfaces so that all transverse modes are coupled to the tunneling path (i.e., to the reaction path for tunneling), with the coupling strength depending on the potential energy surface, in particular on the changes in frequency and vibrational eigenvectors (generalized normal modes) as one proceeds along the reaction path and by reaction-path curvature.…”

Section: Modelsmentioning

confidence: 99%

“…259 (Failure to include this feature made earlier models 377 based on reaction-path curvature inaccurate. 259 ) A key element in the LCT approximation is that it allows a distribution of tunneling paths even at a given energy; 260,347,351 usually the most important aspect of this is tunneling over a range of donor-acceptor distances, as illustrated in Figure 1. This coupling between the tunneling coordinate and the donor-acceptor distance appears also in some models discussed above 65,305,344 and also in related work by Borgis and Hynes.…”

Section: Modelsmentioning

confidence: 99%

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Multidimensional Tunneling, Recrossing, and the Transmission Coefficient for Enzymatic Reactions

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Section: Modelsmentioning

confidence: 99%

Section: Modelsmentioning

confidence: 99%

Section: Modelsmentioning

confidence: 99%

Section: Modelsmentioning

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confidence: 99%

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TheRate: Program forab initio direct dynamics calculations of thermal and vibrational-state-selected rate constants

1998

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We introduce TheRate (THEoretical RATEs), a complete application program with a graphical user interface (GUI) for calculating rate constants from first principles. It is based on canonical variational transition‐state theory (CVT) augmented by multidimensional semiclassical zero and small curvature tunneling approximations. Conventional transition‐state theory (TST) with one‐dimensional Wigner or Eckart tunneling corrections is also available. Potential energy information needed for the rate calculations are obtained from ab initio molecular orbital and/or density functional electronic structure theory. Vibrational‐state‐selected rate constants may be calculated using a diabetic model. TheRate also introduces several technical advancements, namely the focusing technique and energy interpolation procedure. The focusing technique minimizes the number of Hessian calculations required by distributing more Hessian grid points in regions that are critical to the CVT and tunneling calculations and fewer Hessian grid points elsewhere. The energy interpolation procedure allows the use of a computationally less demanding electronic structure theory such as DFT to calculate the Hessians and geometries, while the energetics can be improved by performing a small number of single‐point energy calculations along the MEP at a more accurate level of theory. The CH4+H↔CH3+H2 reaction is used as a model to demonstrate usage of the program, and the convergence of the rate constants with respect to the number of electronic structure calculations. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 1039–1052, 1998

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Effect of a complex formation on the calculated low-pressure rate constant of a bimolecular gas-phase reaction governed by tunneling

1999

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Many important bimolecular hydrogen‐transfer processes that take place in the atmosphere proceed via a potential energy minimum (hydrogen‐bonded complex) that precedes along the minimum energy path the unique saddle point of the reaction, the one corresponding to the hydrogen transfer. It is clear that the one‐step low‐pressure rate constant of such a reaction does not depend on the existence of any complex along the minimum energy path below the reactant if the reaction takes place by thermal activation over a transition state that lies quite above the reactants (for instance 10 kcal/mol). However, we have quantitatively shown in this article that the scenario notoriously changes if the reaction involves significant tunneling. In this work, we have theoretically calculated the rate constants and their temperature dependence for the reaction HO+HOH→HOH+OH by means of a canonical variational transition state theory and a canonical unified statistical theory (when necessary). Multidimensional tunneling effects have been included with a semiclassical transmission coefficient. Two kinds of modified potential energy surfaces (PESs), obtained from an original ab initio potential energy surface, previously calculated by us, have been used. The Eckart‐modified PESs serve to model the hydrogen‐abstraction profiles with no complexes along the path, while the Gaussian‐modified PESs model the energy profiles with two complexes along the path symmetrically distributed at each side of the abstraction saddle point. Our results show that the existence of those complexes reduces the thickness of the classically forbidden region for energies below the adiabatic barrier, and then tunneling is promoted and the reaction is accelerated. The effect of the complex formation in several kinetic magnitudes, as the Arrhenius parameters and the kinetic isotope effect has also been analyzed. © 1999 John Wiley & Sons, Inc. J Comput Chem 20: 1685–1692, 1999

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POLYRATE 4: A new version of a computer program for the calculation of chemical reaction rates for polyatomics

Cited by 543 publications

References 54 publications

Multidimensional Tunneling, Recrossing, and the Transmission Coefficient for Enzymatic Reactions

Multidimensional Tunneling, Recrossing, and the Transmission Coefficient for Enzymatic Reactions

TheRate: Program forab initio direct dynamics calculations of thermal and vibrational-state-selected rate constants

Effect of a complex formation on the calculated low-pressure rate constant of a bimolecular gas-phase reaction governed by tunneling

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