A quasiclassical trajectory study of the Cl + HCN → HCl + CN reaction dynamics. Microscopic reaction mechanism of the H(Cl) + HCN → H2(HCl) + CN reactions

Diego Troya, Miguel González, Guosheng Wu, George C Schatz

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The Cl + HCN → HCl + CN reaction dynamics has been studied using the quasiclassical trajectory method. The potential energy surface is taken from an accurate global surface for the HHCN system. Cl + HCN and H + HCN have very similar energetics, so the present calculation provides a test of whether the Cl + HCN dynamics is captured by a model in which the only difference is provided by the mass of the attacking atom. We find generally good agreement with experimental studies of the Cl + HCN reaction, including CN product rovibrational distributions and the relative rate coefficients for HCN initially in highly excited vibrational states. The results correctly describe the differences between Cl and H attack, so apparently the differences in the reactivity of these two reactions are a kinematic effect. A detailed analysis of the microscopic reaction mechanism of the H + HCN → H2 + CN and Cl + HCN → HCl + CN reactions is also provided. This shows that the H and Cl reactions are both dominated by direct dynamics; however, the direct reaction with Cl frequently involves secondary collisions in which the Cl interacts with the CN fragment of HCN before abstracting the H atom, while the H atom reaction rarely does this. This allows the CN stretch mode to interact more strongly with reaction coordinate motions in Cl + HCN than in H + HCN, leading to greater CN vibrational excitation for initial HCN states that have no C-N stretch excitation, in agreement with observations.

Original languageEnglish
Pages (from-to)2285-2297
Number of pages13
JournalJournal of Physical Chemistry A
Volume105
Issue number11
Publication statusPublished - Mar 22 2001

Fingerprint

Trajectories
trajectories
Atoms
Potential energy surfaces
Kinematics
atoms
vibrational states
attack
excitation
kinematics
reactivity
potential energy
fragments
collisions
coefficients
products

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

A quasiclassical trajectory study of the Cl + HCN → HCl + CN reaction dynamics. Microscopic reaction mechanism of the H(Cl) + HCN → H2(HCl) + CN reactions. / Troya, Diego; González, Miguel; Wu, Guosheng; Schatz, George C.

In: Journal of Physical Chemistry A, Vol. 105, No. 11, 22.03.2001, p. 2285-2297.

Research output: Contribution to journalArticle

@article{8defb6e2db2b40038aa76599e9086ce4,
title = "A quasiclassical trajectory study of the Cl + HCN → HCl + CN reaction dynamics. Microscopic reaction mechanism of the H(Cl) + HCN → H2(HCl) + CN reactions",
abstract = "The Cl + HCN → HCl + CN reaction dynamics has been studied using the quasiclassical trajectory method. The potential energy surface is taken from an accurate global surface for the HHCN system. Cl + HCN and H + HCN have very similar energetics, so the present calculation provides a test of whether the Cl + HCN dynamics is captured by a model in which the only difference is provided by the mass of the attacking atom. We find generally good agreement with experimental studies of the Cl + HCN reaction, including CN product rovibrational distributions and the relative rate coefficients for HCN initially in highly excited vibrational states. The results correctly describe the differences between Cl and H attack, so apparently the differences in the reactivity of these two reactions are a kinematic effect. A detailed analysis of the microscopic reaction mechanism of the H + HCN → H2 + CN and Cl + HCN → HCl + CN reactions is also provided. This shows that the H and Cl reactions are both dominated by direct dynamics; however, the direct reaction with Cl frequently involves secondary collisions in which the Cl interacts with the CN fragment of HCN before abstracting the H atom, while the H atom reaction rarely does this. This allows the CN stretch mode to interact more strongly with reaction coordinate motions in Cl + HCN than in H + HCN, leading to greater CN vibrational excitation for initial HCN states that have no C-N stretch excitation, in agreement with observations.",
author = "Diego Troya and Miguel Gonz{\'a}lez and Guosheng Wu and Schatz, {George C}",
year = "2001",
month = "3",
day = "22",
language = "English",
volume = "105",
pages = "2285--2297",
journal = "Journal of Physical Chemistry A",
issn = "1089-5639",
publisher = "American Chemical Society",
number = "11",

}

TY - JOUR

T1 - A quasiclassical trajectory study of the Cl + HCN → HCl + CN reaction dynamics. Microscopic reaction mechanism of the H(Cl) + HCN → H2(HCl) + CN reactions

AU - Troya, Diego

AU - González, Miguel

AU - Wu, Guosheng

AU - Schatz, George C

PY - 2001/3/22

Y1 - 2001/3/22

N2 - The Cl + HCN → HCl + CN reaction dynamics has been studied using the quasiclassical trajectory method. The potential energy surface is taken from an accurate global surface for the HHCN system. Cl + HCN and H + HCN have very similar energetics, so the present calculation provides a test of whether the Cl + HCN dynamics is captured by a model in which the only difference is provided by the mass of the attacking atom. We find generally good agreement with experimental studies of the Cl + HCN reaction, including CN product rovibrational distributions and the relative rate coefficients for HCN initially in highly excited vibrational states. The results correctly describe the differences between Cl and H attack, so apparently the differences in the reactivity of these two reactions are a kinematic effect. A detailed analysis of the microscopic reaction mechanism of the H + HCN → H2 + CN and Cl + HCN → HCl + CN reactions is also provided. This shows that the H and Cl reactions are both dominated by direct dynamics; however, the direct reaction with Cl frequently involves secondary collisions in which the Cl interacts with the CN fragment of HCN before abstracting the H atom, while the H atom reaction rarely does this. This allows the CN stretch mode to interact more strongly with reaction coordinate motions in Cl + HCN than in H + HCN, leading to greater CN vibrational excitation for initial HCN states that have no C-N stretch excitation, in agreement with observations.

AB - The Cl + HCN → HCl + CN reaction dynamics has been studied using the quasiclassical trajectory method. The potential energy surface is taken from an accurate global surface for the HHCN system. Cl + HCN and H + HCN have very similar energetics, so the present calculation provides a test of whether the Cl + HCN dynamics is captured by a model in which the only difference is provided by the mass of the attacking atom. We find generally good agreement with experimental studies of the Cl + HCN reaction, including CN product rovibrational distributions and the relative rate coefficients for HCN initially in highly excited vibrational states. The results correctly describe the differences between Cl and H attack, so apparently the differences in the reactivity of these two reactions are a kinematic effect. A detailed analysis of the microscopic reaction mechanism of the H + HCN → H2 + CN and Cl + HCN → HCl + CN reactions is also provided. This shows that the H and Cl reactions are both dominated by direct dynamics; however, the direct reaction with Cl frequently involves secondary collisions in which the Cl interacts with the CN fragment of HCN before abstracting the H atom, while the H atom reaction rarely does this. This allows the CN stretch mode to interact more strongly with reaction coordinate motions in Cl + HCN than in H + HCN, leading to greater CN vibrational excitation for initial HCN states that have no C-N stretch excitation, in agreement with observations.

UR - http://www.scopus.com/inward/record.url?scp=0035932665&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035932665&partnerID=8YFLogxK

M3 - Article

VL - 105

SP - 2285

EP - 2297

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 11

ER -