Quantum scattering studies of collisional energy transfer from highly excited polyatomic molecules: A bend-stretch model of He + CS2

György Lendvay, George C Schatz

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

We present the results of an accurate quantum scattering study of collisional energy transfer in a bend-stretch model of the He + CS2 system, considering energies up to 45kcal/mol. These results are generated using a coupled channel method, with vibrational eigenfunctions obtained from a discrete variable representation method. Detailed comparisons with the results of classical trajectory calculations are performed so as to assess classical/quantum correspondence for energy transfer moments, and for the energy transfer probability distribution function. We find good agreement of the energy averaged first moments over a wide range of molecular vibrational energies. The second moments, as well as 〈ΔE〉up and 〈ΔE〉down show less quantitative agreement. The quantum energy transfer distribution functions show considerable mode-specific behavior, but the overall envelope is approximately exponential at large |ΔE\ with a broad spike near |ΔE| = 0. We analyze this behavior in terms of contributions from individual state-to-state transition probabilities. The corresponding classical distribution functions are very similar, showing better correspondence than was found for other models with smaller state densities.

Original languageEnglish
Pages (from-to)587-594
Number of pages8
JournalBerichte der Bunsengesellschaft/Physical Chemistry Chemical Physics
Volume101
Issue number3
Publication statusPublished - 1997

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Energy transfer
Scattering
Distribution functions
Molecules
Eigenvalues and eigenfunctions
Probability distributions
Transfer functions
Trajectories

Keywords

  • Chemical kinetics
  • Computer experiments
  • Energy transfer
  • Quantum mechanics

ASJC Scopus subject areas

  • Chemical Engineering(all)

Cite this

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AU - Schatz, George C

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N2 - We present the results of an accurate quantum scattering study of collisional energy transfer in a bend-stretch model of the He + CS2 system, considering energies up to 45kcal/mol. These results are generated using a coupled channel method, with vibrational eigenfunctions obtained from a discrete variable representation method. Detailed comparisons with the results of classical trajectory calculations are performed so as to assess classical/quantum correspondence for energy transfer moments, and for the energy transfer probability distribution function. We find good agreement of the energy averaged first moments over a wide range of molecular vibrational energies. The second moments, as well as 〈ΔE〉up and 〈ΔE〉down show less quantitative agreement. The quantum energy transfer distribution functions show considerable mode-specific behavior, but the overall envelope is approximately exponential at large |ΔE\ with a broad spike near |ΔE| = 0. We analyze this behavior in terms of contributions from individual state-to-state transition probabilities. The corresponding classical distribution functions are very similar, showing better correspondence than was found for other models with smaller state densities.

AB - We present the results of an accurate quantum scattering study of collisional energy transfer in a bend-stretch model of the He + CS2 system, considering energies up to 45kcal/mol. These results are generated using a coupled channel method, with vibrational eigenfunctions obtained from a discrete variable representation method. Detailed comparisons with the results of classical trajectory calculations are performed so as to assess classical/quantum correspondence for energy transfer moments, and for the energy transfer probability distribution function. We find good agreement of the energy averaged first moments over a wide range of molecular vibrational energies. The second moments, as well as 〈ΔE〉up and 〈ΔE〉down show less quantitative agreement. The quantum energy transfer distribution functions show considerable mode-specific behavior, but the overall envelope is approximately exponential at large |ΔE\ with a broad spike near |ΔE| = 0. We analyze this behavior in terms of contributions from individual state-to-state transition probabilities. The corresponding classical distribution functions are very similar, showing better correspondence than was found for other models with smaller state densities.

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