Observation of bound-free transitions of the linear Ar•••I2(X,v=0) complex in and above the I2 B-X spectral region -: art. no. 131101

Laser-induced fluorescence and action spectroscopy experiments were performed to identify the origin of the Ar center dot center dot center dot I-2 continuum signals observed in and above the I-2 B-X spectral region. We have verified that these signals arise from transitions of the linear Ar center dot center dot center dot I-2(X,v ''=0) complex. The data provides no evidence that the excited state complexes undergo a one-atom caging mechanism when prepared above the I-2(B) dissociation limit, Ar center dot center dot center dot I-2(B)*-> Ar+I+I*-> Ar+I-2(B,v'). Instead, our results indicate that the continuum signals result from bound-free transitions of the linear Ar center dot center dot center dot I-2(X,v ''=0) complex to the inner repulsive walls of numerous Ar+I-2(B,v(')) intermolecular potentials. The bound-free continuum signal associated with transitions to each Ar+I-2(B,v(')) potential spans an energy region >700 cm(-1). We have found that the continuum signals turn-on 250(2)cm(-1) above the corresponding I-2 B-X,v(')-0 band origin, and this energy represents the binding energy of the linear Ar center dot center dot center dot I-2(X,v ''=0) conformer, D-0''(L)=250(2)cm(-1). (C) 2005 American Institute of Physics.