### Abstract

The dynamics of vibrational relaxation in polyatomic van der Waals clusters is investigated theoretically, using as an example a one-dimensional model of I_{2}(Ne)_{N} with excited I_{2} vibration. The method employed is classical dynamics simplified by the time-dependent self-consistent-field (TDSCF) approximation. The dependence of the relaxation on cluster size is examined, with calculations for N = 4, 8, 16 and with extrapolation to N—representing I_{2} in a solid Ne matrix. Also studied is the variation of the relaxation mechanism with initial vibrational state υ, in the range υ = 25-60. The main results are: (i) Relaxation can be interpreted best as affected by collisions between I_{2} and neighbouring Ne atoms. Collective modes do not, in most cases, play a significant role in the relaxation, (ii) The I_{2} centre-of-mass vibration plays a less significant role than the Ne atoms in the redistribution of the released vibrational energy in the cluster, (iii) The initial relaxation rate decreases with cluster size, the lifetime of υ = 28 being τ = 3-6 ps for N = 4 and τ = 51 ps for N = S. This is due to decreasing frequency of impulsive I_{2}-Ne ' collisions' in the larger clusters, (iv) Initial relaxation behaviour and rates for the N = 16 cluster appear converged to those of the corresponding solid matrix, (v) relaxation dynamics switches from weak to strong coupling-type behaviour as υ increases from 35 to 60.

Original language | English (US) |
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Pages (from-to) | 47-64 |

Number of pages | 18 |

Journal | Molecular Physics |

Volume | 56 |

Issue number | 1 |

DOIs | |

State | Published - Sep 1985 |

### ASJC Scopus subject areas

- Biophysics
- Molecular Biology
- Condensed Matter Physics
- Physical and Theoretical Chemistry

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## Cite this

_{2}(Ne)

_{n}; n = 4, 8, 16.

*Molecular Physics*,

*56*(1), 47-64. https://doi.org/10.1080/00268978500102151