Experimental and theoretical studies of the reaction of atomic hydrogen with silane

Goumri, Abdellatif; Yuan, Wenhao; Ding, Luying; Shi, Youchun; Marshall, Paul

doi:10.1016/0301-0104(93)80192-c

Cited by 51 publications

(58 citation statements)

References 43 publications

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“…[43][44][45][46] The photochemical reactor is a stainless steel six-way cross heated within an oven. Gas temperatures T in the reaction zone, where the arms of the reactor (i.d. )…”

Section: Experimental Methodsmentioning

confidence: 99%

Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-Evaluation

et al. 2009

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A quantitative understanding of the thermochemistry of cyclohexadienyl radical and 1,4-cyclohexadiene is beneficial for diverse areas of chemistry. Given the interest in these two species, it is surprising that more detailed thermodynamic data concerning the homolytic C-H bond enthalpies of such entities have not been forthcoming. We thus undertook an experimental and computational evaluation of (a) the enthalpy of formation of cyclohexadienyl radical (C 6 H 7 ), (b) the homolytic C-H bond enthalpy of 1,4-cyclohexadiene (C 6 H 8 ), and (c) the enthalpy of the addition of a hydrogen atom to benzene. Using laser photolysis experiments coupled with highly accurate ab initio quantum mechanical techniques, a newly recommended enthalpy of formation for C 6 H 7 is determined to be 208.0 ( 3.9 kJ mol -1 , leading to a homolytic bond dissociation enthalpy of 321.7 ( 2.9 kJ mol -1 , almost 9 kJ mol -1 higher than previously determined enthalpies that used less certain experimental values for the C 6 H 7 enthalpy of formation.

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“…[43][44][45][46] The photochemical reactor is a stainless steel six-way cross heated within an oven. Gas temperatures T in the reaction zone, where the arms of the reactor (i.d. )…”

Section: Experimental Methodsmentioning

confidence: 99%

Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-Evaluation

et al. 2009

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“…They inferred that the exchange channel proceeds through an inversion mechanism. Several theoretical investigations have been reported on HϩSiH 4 reactions, although earlier ab initio calculations were limited to the small regions around a few stationary points and the minimum energy path (MEP) (18,(21)(22)(23). So far there have been two PESs reported (24,25) for the SiH 5 system, but both of them could only describe reaction R1: Espinosa-García et al (24) developed an analytic semiempirical PES in 1998; more recently, Wang et al (25) constructed a 12-dimensional ab initio PES based on the modified Shepard interpolation method (26)(27)(28) and Ϸ1,300 ab initio reference points.…”

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confidence: 99%

Quasiclassical trajectory study of H+SiH ₄ reactions in full-dimensionality reveals atomic-level mechanisms

Cao

Zhang

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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potential energy surface ͉ reaction dynamics T he AϩBC type reactions have long served as benchmarks in the development of the kinetics and dynamics theories of chemical reactions (1-5). However, behavior of polyatomic reactions may be qualitatively different from what has been deduced from studies of atom-diatom dynamics. For example, a major reaction path, which does not follow the intrinsic reaction coordinate, has recently been found by Hase et al. (6) in their quasiclassical trajectory (QCT) study on the F Ϫ ϩCH 3 OOH reaction. Another example is the reaction of HϩCH 4 (and its isotopic variants), for which recent investigations (7) have focused on the new stripping mechanism observed by Zare and coworkers (8-9). The rebound mechanism is well-known for the HϩD 2 reaction (10-11), and a lot of polyatomic H abstraction reactions, including HϩCD 4 , have long been considered to proceed through this mechanism. However, in the recent combined experimental and theoretical studies on the reaction of HϩCD 4 (9, 12), the stripping mechanism was proposed, in which the velocity of incoming H atom is perpendicular to the C-D bond and the HD product is carried into the forward hemisphere. The stripping mechanism was further confirmed by Bowman and coworkers (13) using the QCT method.The HϩSiH 4 reaction is an analogue to HϩCH 4 , and both abstraction and exchange reactions can happen; i.e., Unlike the HϩCH 4 abstraction reaction, which is nearly thermoneutral, the HϩSiH 4 abstraction reaction R1 is exothermic by Ϸ13 kcal/mol, and regarded as a prototype of exothermic polyatomic H abstraction reactions. Also, as we will demonstrate, both reactions 1 (R1) and 2 (R2) could happen at collision energies above Ϸ12.5 kcal/mol, therefore the HϩSiH 4 reaction is actually a better candidate for studying the competition between abstraction and exchange than HϩCH 4 , for which the exchange channel is not open at collision energies Ͻ35 kcal/mol (noninversion exchange not open at Ͻ60 kcal/mol) (14). AbstractionIn this work, a global 12-dimensional potential energy surface (PES) that describes both abstraction and exchange reactions for the SiH 5 system is constructed, and detailed QCT calculations for both reactions R1 and R2 on this ab initio PES are performed, which yield insights into the reaction mechanism. The computed product angular distributions indicate that the abstraction reaction is a combination of rebound and stripping. More importantly, here we propose that the HϩSiH 4 exchange reaction is a combination of three mechanisms, inversion, torsion (more exactly, torsion-tilt), and side-inversion as demonstrated in Fig. 1. The interesting dynamical features for exchange can be explained with these atomic-level mechanisms. These findings are helpful for our understanding of the nature of polyatomic reactions, which goes beyond the atom-diatom pictures, and would have implications for a number of fields ranging from fundamental reaction dynamics to atmospheric and organic chemistry.The HϩSiH 4 reaction is important in the the...

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“…where the overall observed rate constant, summarized by eq 5, is the product of the concentration equilibrium constant for adduct formation K c , equal to the ratio of forward and reverse rate constants, and the rate constant for adduct fragmentation, defined here as k 6 . The nature of the fragments is unknown.…”

Section: Discussionmentioning

confidence: 99%

The Kinetics of the Reaction of H Atoms with C₄F₆

Goumri

Marshall

2001

J. Phys. Chem. A

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The rate constant k for the gas-phase reaction of atomic hydrogen with 1,1,2,3,4,4-hexafluoro-1,3-butadiene has been measured over the temperature range 290-1010 K by time-resolved atomic resonance fluorescence using H 2 O and NH 3 as precursors, at argon pressures of about 30-140 mbar. Over the range 290-620 K a positive activation energy was observed, k ) (3.40 ( 0.34) × 10 -11 exp[(-16.7 ( 0.4) kJ mol -1

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Experimental and theoretical studies of the reaction of atomic hydrogen with silane

Cited by 51 publications

References 43 publications

Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-Evaluation

Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-Evaluation

Quasiclassical trajectory study of H+SiH ₄ reactions in full-dimensionality reveals atomic-level mechanisms

The Kinetics of the Reaction of H Atoms with C₄F₆

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Experimental and theoretical studies of the reaction of atomic hydrogen with silane

Cited by 51 publications

References 43 publications

Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-Evaluation

Enthalpy of Formation of the Cyclohexadienyl Radical and the C−H Bond Enthalpy of 1,4-Cyclohexadiene: An Experimental and Computational Re-Evaluation

Quasiclassical trajectory study of H+SiH 4 reactions in full-dimensionality reveals atomic-level mechanisms

The Kinetics of the Reaction of H Atoms with C4F6

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Quasiclassical trajectory study of H+SiH ₄ reactions in full-dimensionality reveals atomic-level mechanisms

The Kinetics of the Reaction of H Atoms with C₄F₆