Identification of bound-free transitions of the linear ArI2 complex throughout the I2 BX region

PHYS 78

Joshua P. Darr, jpdarr@artsci.wustl.edu, John Glennon, jglennon@wustl.edu, and Richard A. Loomis, loomis@wustl.edu. Department of Chemistry, Washington University, 1 Brookings Drive, Saint Louis, MO 63130-4899
Discrete features associated with transitions of both the T-shaped and linear Ar•••I2(X,v″=0) complexes are observed in laser-induced fluorescence and action spectroscopy experiments performed throughout the I2 BX electronic region. The binding energy of the linear conformer is directly measured to be 250(2) cm1, 10 to 15 cm1 greater than the T-shaped conformer. Continuum signals are observed in the spectra that continue to energies well above the I2(B) dissociation limit. Our results indicate that the continuum signals can be attributed to transitions of the linear Ar•••I2(X,v″=0) complex to the inner, repulsive walls of many Ar + I2(B,v′) intermolecular potentials. The excited state complexes are thus very short lived and undergo direct dissociation into Ar + I2(B,v′) products. There is no evidence for the previously proposed one-atom caging mechanism.