Exact quantum and vibrationally adiabatic quantum, semiclassical and quasiclassical study of the collinear reactions Cl + MuCl, Cl + HCl, Cl + DCl

Bondi, D. K.; Connor, J. N. L.; Manz, J.; Römelt, J.

doi:10.1080/00268978300102491

Cited by 160 publications

(72 citation statements)

References 80 publications

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“…Instead they were derived for the well-studied H+ Clz~HCl+ Cl rearrangement that occurs on the same surface. The BCMR surface (Bondi et al , 1983) was, however, explicitly optimized to At Cl+HC1 rate data. Figure 4 plots this surface for its most favorable (linear) reaction path.…”

Section: B Cl+hcimentioning

confidence: 99%

The analytical representation of electronic potential-energy surfaces

1989

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This article reviews the commonly used methods for representing electronic potential-energy surfaces for small molecules and simple chemical reactions in terms of globally defined analytical functions. Four classes of methods are discussed: spline fitting methods, semiempirical methods, many-body expansion methods, and methods that represent global surfaces based on information determined along reaction paths. The application of these methods is examined in detail for four triatomic systems and one fouratom system: 0( P)+H2, Cl+HCl, H+CO, 0('D)+H2 H20~0H+H, and H+C02 OH+CO.These examples illustrate both the art and the pitfalls of representing surfaces. In addition, the consequences of different potential surface representations for the dynamics of collisions on these surfaces are discussed at length.

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Section: B Cl+hcimentioning

confidence: 99%

The analytical representation of electronic potential-energy surfaces

1989

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“…Due to its small mass (0.11398 u), collisions involving Mu atoms have constituted a sensitive probe for the importance of ZPE and tunnelling in chemical reactions [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. In turn, C Heμ [11,12,32], whose mass amounts to 4.11548 u, is formed when one of the He electrons is substituted by a negative muon μ − , 206.77 times heavier than the electron.…”

Section: Introductionmentioning

confidence: 99%

Understanding the reaction between muonium atoms and hydrogen molecules: zero point energy, tunnelling, and vibrational adiabaticity

et al. 2013

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The advent of very precise measurements of rate coefficients in reactions of muonium (Mu), the lightest hydrogen isotope, with H 2 in its ground and first vibrational state and of kinetic isotope effects with respect to heavier isotopes has triggered a renewed interests in the field of muonic chemistry. The aim of the present article is to review the most recent results about the dynamics and mechanism of the reaction Mu + H 2 to shed light on the importance of quantum effects such as tunnelling, the preservation of the zero point energy, and the vibrational adiabaticity. In addition to accurate quantum mechanical (QM) calculations, quasiclassical trajectories (QCT) have been run in order to check the reliability of this method for this isotopic variant. It has been found that the reaction with H 2 (v=0) is dominated by the high zero point energy (ZPE) of the products and that tunnelling is largely irrelevant. Accordingly, both QCT calculations that preserve the products' ZPE as well as those based on the Ring Polymer Molecular Dynamics methodology can reproduce the QM rate coefficients. However, when the hydrogen molecule is vibrationally excited, QCT calculations fail completely in the prediction of the huge vibrational enhancement of the reactivity. This failure is attributed to tunnelling, which plays a decisive role breaking the vibrational adiabaticity when v=1. By means of the analysis of the results, it can be concluded that the tunnelling takes place through the ν 1 =1 collinear barrier. Somehow, the tunnelling that is missing in the Mu + H 2 (v=0) reaction is found in Mu + H 2 (v=1).

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“…ti (b) for the spin-orbit terms, we have q; = +(j + 1) -L(L + 1) -S(S + l)]S, (11) ti2 (c) for the Coriolis terms, we have…”

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confidence: 99%

Influence of Atomic Fine Structure on Bimolecular Rate Constants: The Cl(2P) + HCl Reaction

Schatz¹

1995

J. Phys. Chem.

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In this paper we use quantum reactive scattering calculations to study the influence of atomic fine structure on the rate constants for atom-diatom reactions, using the C1(2P) + HC1 reaction as an example. To do this, we calculate rate constants using two different methods, first a conventional single surface reactive scattering method based on propagating coupled channel equations using hyperspherical coordinates, and second a multiple surface method in which the electronic fine structure of the C1 is explicitly included in the calculation. In this second calculation, the Hamiltonian combines the nonrelativistic potential surfaces for the 2C and 211 states of ClHCl with a spin-orbit Hamiltonian in which the spin-orbit parameter is taken to be a constant and with Coriolis-induced electronic and rotational couplings. Rate constants are evaluated using the J-shifting approximation, using J = l/2 calculations as the reference. We find that the biggest effect of the fine structure is a static one which arises because the spin-orbit term in the Hamiltonian stabilizes the reagents and products differently than the 2Z1/2 saddle point. This causes the activation energy to increase by about 29% of the atomic 2P1/2 -zP3/2 energy difference. When this effect is factored out, the single and multiple surface rate constants are found to be in very good agreement (provided that the usual electronic statistical factors are applied to the single surface rate constant), with differences of less than 20% over the temperature range that we considered. We also study how the size of the spin-orbit constant influences this result, and we find that the overall rate is relatively insensitive to spin-orbit splitting (except for the shift in activation energy). Fine structure resolved rate constants for C1(2P1/2) are found to vary by many orders of magnitude as the spin-orbit splitting is varied between zero and the experimental value, corresponding to a change in the dynamics from statistical to adiabatic limits

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Exact quantum and vibrationally adiabatic quantum, semiclassical and quasiclassical study of the collinear reactions Cl + MuCl, Cl + HCl, Cl + DCl

Cited by 160 publications

References 80 publications

The analytical representation of electronic potential-energy surfaces

The analytical representation of electronic potential-energy surfaces

Understanding the reaction between muonium atoms and hydrogen molecules: zero point energy, tunnelling, and vibrational adiabaticity

Influence of Atomic Fine Structure on Bimolecular Rate Constants: The Cl(2P) + HCl Reaction

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