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Title: Quantum dynamics of van der Waals clusters: Model results for He[sub 2]Cl[sub 2] and Ne[sub 2]Cl[sub 2] fragmentation

Journal Article · · Journal of Chemical Physics; (United States)
DOI:https://doi.org/10.1063/1.464912· OSTI ID:6698054
;  [1]
  1. Theoretical Chemistry Group, Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

Wave packet calculations are carried out on a three degrees of freedom model for the fragmentation dynamics of X[sub 2]Cl[sub 2] van der Waals clusters, with X=He and Ne. The model allows Cl[sub 2] to vibrate, but not rotate, with the X atoms restricted to motion in a plane perpendicular to and bisecting the Cl[sub 2] bond. The (X, Cl[sub 2] center, X) angle [theta] is also held fixed. Both X+XCl[sub 2] and 2X+Cl[sub 2] continua are explicitly included. Results for He[sub 2]Cl[sub 2]([ital v][prime]) vibrational predissociation to 2He+Cl[sub 2]([ital v][sub [ital F]]), with 7[le][ital v][prime][le]13 are presented, and found to be in qualitative accord with experiment. In particular, even though products Cl[sub 2]([ital v][sub [ital F]]=[ital v][prime][minus]1) are energetically allowed for all [ital v][prime] in the range, [approx]90% of the products are estimated to be in [ital v][sub [ital F]]=[ital v][prime][minus]2. Inspection of the wave packet confirms that a sequential mechanism He[sub 2]Cl[sub 2]([ital v][prime])[r arrow]He+HeCl[sub 2]([ital v][prime][minus]1)[r arrow]2He+Cl[sub 2]([ital v][sub [ital F]]=[ital v][prime][minus]2) is operative. Theoretical lifetimes for Ne[sub 2]Cl[sub 2]([ital v][prime])[r arrow]2Ne+Cl[sub 2]([ital v][sub [ital F]]) are in rough agreement with experimental results, where available. The Cl[sub 2]([ital v][sub [ital F]]) product distributions for Ne[sub 2]Cl[sub 2]([ital v][prime]) are estimated to be similar to those obtained for He[sub 2]Cl[sub 2]([ital v][prime]), with [ital v][sub [ital F]]=[ital v][prime][minus]2 products being dominant over the entire [ital v][prime] range. This is only partly in accord with experiment, which points to both [ital v][sub [ital F]]=[ital v][prime][minus]1 and [ital v][sub [ital F]]=[ital v][prime][minus]2 products being important when the [ital v][prime][minus]1 product channel is open (for [ital v][prime][le]10 in this case).

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
6698054
Journal Information:
Journal of Chemical Physics; (United States), Vol. 98:7; ISSN 0021-9606
Country of Publication:
United States
Language:
English