### 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 |
---|---|

Pages (from-to) | 47-64 |

Number of pages | 18 |

Journal | Molecular Physics |

Volume | 56 |

Issue number | 1 |

DOIs | |

Publication status | Published - 1985 |

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### ASJC Scopus subject areas

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

### Cite this

_{2}(Ne)

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

*Molecular Physics*,

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

**Relaxation of vibrationally highly excited diatomics in van der waals clusters a study of I _{2}(Ne)_{n}; n = 4, 8, 16.** / Eslava, L. A.; Gerber, R. B.; Ratner, Mark A.

Research output: Contribution to journal › Article

_{2}(Ne)

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

*Molecular Physics*, vol. 56, no. 1, pp. 47-64. https://doi.org/10.1080/00268978500102151

}

TY - JOUR

T1 - Relaxation of vibrationally highly excited diatomics in van der waals clusters a study of I2(Ne)n; n = 4, 8, 16

AU - Eslava, L. A.

AU - Gerber, R. B.

AU - Ratner, Mark A

PY - 1985

Y1 - 1985

N2 - The dynamics of vibrational relaxation in polyatomic van der Waals clusters is investigated theoretically, using as an example a one-dimensional model of I2(Ne)N with excited I2 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 I2 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 I2 and neighbouring Ne atoms. Collective modes do not, in most cases, play a significant role in the relaxation, (ii) The I2 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 I2-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.

AB - The dynamics of vibrational relaxation in polyatomic van der Waals clusters is investigated theoretically, using as an example a one-dimensional model of I2(Ne)N with excited I2 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 I2 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 I2 and neighbouring Ne atoms. Collective modes do not, in most cases, play a significant role in the relaxation, (ii) The I2 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 I2-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.

UR - http://www.scopus.com/inward/record.url?scp=84946660903&partnerID=8YFLogxK

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U2 - 10.1080/00268978500102151

DO - 10.1080/00268978500102151

M3 - Article

VL - 56

SP - 47

EP - 64

JO - Molecular Physics

JF - Molecular Physics

SN - 0026-8976

IS - 1

ER -