### Abstract

We present a fully quantal dynamical study of vibrational relaxation of CO in collisions with H_{2} treating H_{2} as a structureless projectile. The potential energy surface consists of a SCF part, including explicitly the variation with the CO bond distance, and a damped long range dispersion part. This potential model contains only two free parameters in the damping function which have been determined previously by fitting rotationally inelastic beam data for D_{2}-CO. The dynamical calculations are performed within the infinite order sudden approximation (IOSA) and the coupled states approximation (CSA). The IOSA relaxation cross sections are generally a factor of ∼1.5 smaller than the CSA cross sections independent on the initial rotational state of CO for j≲4-6. The relaxation rate constants are very sensitive to small changes of the interaction potential. After readjusting one of the damping parameters (within a range still acceptable with the beam data) the IOSA rate constants agree very well with the experimental ones for ortho H_{2}. It is demonstrated that on the same level of approximation the present rate constants are about three times larger than those obtained from the potential energy surface of Poulsen.

Original language | English (US) |
---|---|

Pages (from-to) | 236-244 |

Number of pages | 9 |

Journal | The Journal of chemical physics |

Volume | 82 |

Issue number | 1 |

State | Published - 1985 |

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### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics

### Cite this

*The Journal of chemical physics*,

*82*(1), 236-244.

**Vibrational relaxation of CO (n=1) in collisions with H2-. I. Potential energy surface and test of dynamical approximations.** / Bacic, Zlatko; Schinke, R.; Diercksen, G. H F.

Research output: Contribution to journal › Article

*The Journal of chemical physics*, vol. 82, no. 1, pp. 236-244.

}

TY - JOUR

T1 - Vibrational relaxation of CO (n=1) in collisions with H2-. I. Potential energy surface and test of dynamical approximations

AU - Bacic, Zlatko

AU - Schinke, R.

AU - Diercksen, G. H F

PY - 1985

Y1 - 1985

N2 - We present a fully quantal dynamical study of vibrational relaxation of CO in collisions with H2 treating H2 as a structureless projectile. The potential energy surface consists of a SCF part, including explicitly the variation with the CO bond distance, and a damped long range dispersion part. This potential model contains only two free parameters in the damping function which have been determined previously by fitting rotationally inelastic beam data for D2-CO. The dynamical calculations are performed within the infinite order sudden approximation (IOSA) and the coupled states approximation (CSA). The IOSA relaxation cross sections are generally a factor of ∼1.5 smaller than the CSA cross sections independent on the initial rotational state of CO for j≲4-6. The relaxation rate constants are very sensitive to small changes of the interaction potential. After readjusting one of the damping parameters (within a range still acceptable with the beam data) the IOSA rate constants agree very well with the experimental ones for ortho H2. It is demonstrated that on the same level of approximation the present rate constants are about three times larger than those obtained from the potential energy surface of Poulsen.

AB - We present a fully quantal dynamical study of vibrational relaxation of CO in collisions with H2 treating H2 as a structureless projectile. The potential energy surface consists of a SCF part, including explicitly the variation with the CO bond distance, and a damped long range dispersion part. This potential model contains only two free parameters in the damping function which have been determined previously by fitting rotationally inelastic beam data for D2-CO. The dynamical calculations are performed within the infinite order sudden approximation (IOSA) and the coupled states approximation (CSA). The IOSA relaxation cross sections are generally a factor of ∼1.5 smaller than the CSA cross sections independent on the initial rotational state of CO for j≲4-6. The relaxation rate constants are very sensitive to small changes of the interaction potential. After readjusting one of the damping parameters (within a range still acceptable with the beam data) the IOSA rate constants agree very well with the experimental ones for ortho H2. It is demonstrated that on the same level of approximation the present rate constants are about three times larger than those obtained from the potential energy surface of Poulsen.

UR - http://www.scopus.com/inward/record.url?scp=0011769489&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0011769489&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0011769489

VL - 82

SP - 236

EP - 244

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 1

ER -