AR2CL2 AND AR3CL2 - STRUCTURE, BOND-ENERGY, AND DISSOCIATION DYNAMICS

The structure, bond energy, and dissociation dynamics of the Ar2Cl2 and Ar3Cl2 van der Waals molecules are studied by a laser pump-probe technique. Ar2Cl2 is found to be a distorted tetrahedron with an Ar2-Cl2 distance of 3.9 ± 0.5 Å and an Ar-Ar bond distance of 4.1 ± 0.6 Å. For Ar3Cl2 there is evidence that two isomers exist. In the low-energy isomer, the three argon atoms form a triangle and the Cl2 bonds with its axis parallel to the triangle. In the higher energy, 1 cm-1, isomer the argon atoms each bond perpendicular to the Cl2 axis. The total van der Waals bond energy is found to be 447.5 ± 3.5 cm-1 for Ar2Cl2 in the ground electronic state and 776 ± 3 cm-1 for Ar3Cl2 in the ground electronic state. The chlorine fragment rotational-state population distribution produced by the vibrational predissociation of Ar2Cl2 is found to be nearly statistical by surprisal analysis. The chlorine product-rotational-state distribution for the dissociation of the Ar3Cl2 complex can be described by a Boltzmann distribution. © 1990 American Chemical Society.