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, M. A.

N1 - Funding Information:
This work was done when L.A.E. was a holder of a Faculty of Sciences Postdoctoral Fellowship at the Hebrew University. The Fritz Haber Center at the H.U. is supported by the Minerva Gesellschaft fur die Forschung, Munchen, Federal Republic of Germany. M.R. thanks the Chemistry Division of the NSF for partial support.

PY - 1985/9

Y1 - 1985/9

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

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

U2 - 10.1080/00268978500102151

DO - 10.1080/00268978500102151

M3 - Article

AN - SCOPUS:84946660903

VL - 56

SP - 47

EP - 64

JO - Molecular Physics

JF - Molecular Physics

SN - 0026-8976

IS - 1

ER -