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 · Thu Apr 01 04:00:00 EST 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.464912· OSTI ID:6698054

Le Quere, F; Gray, S K ^[1]

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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), Journal Name: Journal of Chemical Physics; (United States) Vol. 98:7; ISSN 0021-9606; ISSN JCPSA6
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
CHLORIDES
CHLORINE COMPOUNDS
DISSOCIATION
ENERGY LEVELS
EXCITED STATES
HALIDES
HALOGEN COMPOUNDS
HELIUM CHLORIDES
HELIUM COMPOUNDS
MECHANICS
NEON CHLORIDES
NEON COMPOUNDS
PREDISSOCIATION
QUANTUM MECHANICS
RARE GAS COMPOUNDS
VAN DER WAALS FORCES
VIBRATIONAL STATES
WAVE PACKETS