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

L. A. Eslava, R. B. Gerber, Mark A Ratner

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5 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)47-64
Number of pages18
JournalMolecular Physics
Volume56
Issue number1
DOIs
Publication statusPublished - 1985

ASJC Scopus subject areas

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

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