Reaction dynamics calculations for the CN+H2→HCN+H reaction: Applications of the rotating-bond approximation

Takayanagi, Toshiyuki; Schatz, George C.

doi:10.1063/1.473061

Cited by 52 publications

(20 citation statements)

References 28 publications

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“…To test this hypothesis, Takayanagi and Schatz carried out quantum scattering calculations on the related HϩHCN reactions allowing the CN bond to vibrate while constraining HHC to be collinear, a geometry that removes the possibility of complex formation. 22 These calculations confirm that excitation to HCN͑100͒, i.e., one quantum of mostly CN stretch character, significantly enhances the reaction cross section to form H 2 ϩCN and lowers the threshold energy relative to HϩHCN͑000͒. In fact, the threshold is predicted to be lowered by nearly 100% of the added vibrational energy, which would be more consistent with direct vibrationally mediated coupling into the reaction coordinate.…”

Section: Introductionmentioning

confidence: 55%

Intramolecular energy flow and nonadiabaticity in vibrationally mediated chemistry: Wave packet studies of Cl+H2O

Fair

Schaefer

Kosloff

et al. 2002

The Journal of Chemical Physics

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Time-dependent and time-independent quantum scattering methods are used to investigate state-to-state inelastic and reactive collision dynamics for a three-dimensional ͑3D͒ atomϩtriatom model of ClϩH 2 O→HClϩOH. The results elucidate the role of ͑i͒ intramolecular vibrational energy transfer and ͑ii͒ vibrational nonadiabaticity on the time scale of a reactive encounter in systems with nearly degenerate stretching ''local modes.'' Adiabatic two-dimensional ͑2D͒ vibrational eigenfunctions ͓ n (r 1 ,r 2 ,R)͔ and eigenvalues ͓E n (R)͔ are first obtained in OH bond coordinates (r 1 ,r 2) as a function of Cl-H 2 O center-of-mass separation ͑R͒, which then provides the requisite adiabatic potential energy curves and nonadiabatic coupling matrix elements for full 3D quantum wave packet propagation. Inspection of these 2D vibrational eigenfunctions indicates that near degeneracy between H 2 O symmetric ͉01 ϩ ͘ and antisymmetric ͉01 Ϫ ͘ states is systematically lifted as R decreases, causing vibrational energy to flow into local-mode OH excitations pointing either toward ͑''proximal''͒ or away from ͑''distal''͒ the approaching Cl atom, respectively. This suggests a simple yet powerful physical model for mode-specific reactive scattering dynamics, the predictions of which are confirmed by full 3D quantum wave packet calculations over a range of collision velocities.

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Section: Introductionmentioning

confidence: 55%

Intramolecular energy flow and nonadiabaticity in vibrationally mediated chemistry: Wave packet studies of Cl+H2O

Fair

Schaefer

Kosloff

et al. 2002

The Journal of Chemical Physics

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“…This approach has been extended to tetra atomic systems like OH/CO 71 and OH/H 2 together with their isotopic variants, 72 and CN/H 2 (D 2 ). 73 These simple systems are prototypical reactions in bridging our theoretical understanding of reactive scattering, via dynamics calculations on chemically accurate potential energy surfaces, with experimental observations. 74 These dynamics calculations are needed to turn the ab initio results into quantities that can be compared with experiments.…”

Section: Experimental Approachmentioning

confidence: 99%

Untangling the chemical evolution of Titan's atmosphere and surface–from homogeneous to heterogeneous chemistry

et al. 2010

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“…Detailed experimental studies of three-atom systems such as bimolecular collisions of chlorine (Cl), , fluorine (F), deuterium (D), carbon (C), , nitrogen (N), − oxygen (O), , and sulfur (S) , with molecular hydrogen (H 2 ) established experimental benchmarks. The crossed beam approach has been successfully extended to four-atom [OH/CO, − OH/H 2 , ,, CN/H 2 ], five-atom [C/C 2 H 2 ], and even six-atom systems [Cl/CH 4 , , F/CD 4 − ] bridging our theoretical understanding of reactive scattering dynamics on chemically accurate potential energy surfaces with experimental observations . With the development of powerful theoretical models, attention has turned during the last few years to more complex systems of fundamental applications in catalysis, combustion processes, and interstellar chemistry along with planetary atmospheres.…”

Section: Introductionmentioning

confidence: 99%

A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X²Π) with Methylacetylene (CH₃CCH; X¹A₁) and D4-Methylacetylene (CD₃CCD; X¹A₁)

et al. 2016

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The bimolecular gas-phase reactions of the ground-state silylidyne radical (SiH; X(2)Π) with methylacetylene (CH3CCH; X(1)A1) and D4-methylacetylene (CD3CCD; X(1)A1) were explored at collision energies of 30 kJ mol(-1) under single-collision conditions exploiting the crossed molecular beam technique and complemented by electronic structure calculations. These studies reveal that the reactions follow indirect scattering dynamics, have no entrance barriers, and are initiated by the addition of the silylidyne radical to the carbon-carbon triple bond of the methylacetylene molecule either to one carbon atom (C1; [i1]/[i2]) or to both carbon atoms concurrently (C1-C2; [i3]). The collision complexes [i1]/[i2] eventually isomerize via ring-closure to the c-SiC3H5 doublet radical intermediate [i3], which is identified as the decomposing reaction intermediate. The hydrogen atom is emitted almost perpendicularly to the rotational plane of the fragmenting complex resulting in a sideways scattering dynamics with the reaction being overall exoergic by -12 ± 11 kJ mol(-1) (experimental) and -1 ± 3 kJ mol(-1) (computational) to form the cyclic 2-methyl-1-silacycloprop-2-enylidene molecule (c-SiC3H4; p1). In line with computational data, experiments of silylidyne with D4-methylacetylene (CD3CCD; X(1)A1) depict that the hydrogen is emitted solely from the silylidyne moiety but not from methylacetylene. The dynamics are compared to those of the related D1-silylidyne (SiD; X(2)Π)-acetylene (HCCH; X(1)Σg(+)) reaction studied previously in our group, and from there, we discovered that the methyl group acts primarily as a spectator in the title reaction. The formation of 2-methyl-1-silacycloprop-2-enylidene under single-collision conditions via a bimolecular gas-phase reaction augments our knowledge of the hitherto poorly understood silylidyne (SiH; X(2)Π) radical reactions with small hydrocarbon molecules leading to the synthesis of organosilicon molecules in cold molecular clouds and in carbon-rich circumstellar envelopes.

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Reaction dynamics calculations for the CN+H2→HCN+H reaction: Applications of the rotating-bond approximation

Abstract: New results for the OH (ν=0,j=0)+ CO (ν=0,j=0)→ H + CO 2 reaction: Five-and full-dimensional quantum dynamical study on several potential energy surfaces Effects of reagent rotation and the accuracy of the centrifugal sudden approximation in the H 2 +CN reaction

Cited by 52 publications

References 28 publications

Intramolecular energy flow and nonadiabaticity in vibrationally mediated chemistry: Wave packet studies of Cl+H2O

Intramolecular energy flow and nonadiabaticity in vibrationally mediated chemistry: Wave packet studies of Cl+H2O

Untangling the chemical evolution of Titan's atmosphere and surface–from homogeneous to heterogeneous chemistry

A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X²Π) with Methylacetylene (CH₃CCH; X¹A₁) and D4-Methylacetylene (CD₃CCD; X¹A₁)

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Reaction dynamics calculations for the CN+H2→HCN+H reaction: Applications of the rotating-bond approximation

Abstract: New results for the OH (ν=0,j=0)+ CO (ν=0,j=0)→ H + CO 2 reaction: Five-and full-dimensional quantum dynamical study on several potential energy surfaces Effects of reagent rotation and the accuracy of the centrifugal sudden approximation in the H 2 +CN reaction

Cited by 52 publications

References 28 publications

Intramolecular energy flow and nonadiabaticity in vibrationally mediated chemistry: Wave packet studies of Cl+H2O

Intramolecular energy flow and nonadiabaticity in vibrationally mediated chemistry: Wave packet studies of Cl+H2O

Untangling the chemical evolution of Titan's atmosphere and surface–from homogeneous to heterogeneous chemistry

A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X2Π) with Methylacetylene (CH3CCH; X1A1) and D4-Methylacetylene (CD3CCD; X1A1)

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A Combined Experimental and Theoretical Study on the Formation of the 2-Methyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reactions of the Silylidyne Radical (SiH; X²Π) with Methylacetylene (CH₃CCH; X¹A₁) and D4-Methylacetylene (CD₃CCD; X¹A₁)