THE INFRARED-SPECTROSCOPY AND DYNAMICS OF OCO-HCL AND SCO-HCL - AN EXAMPLE OF MODE-SPECIFIC INTERMOLECULAR ENERGY-TRANSFER

Optothermal near infrared laser spectroscopy has been used to study th e OCO-HCl and SCO-HCl complexes by exciting the H-Cl stretch using an F-center laser. In both cases, the two isotopic forms associated with (HCl)-Cl-35 and (HCl)-Cl-37 have been observed. All of the observed sp ectra are consistent with and analyzed in terms of a linear structure. Vibrational predissociation is observed to be abnormally fast in the OCO-HCl complex, considering the rather weak coupling between the inte rmolecular degrees of freedom and the H-Cl stretch suggested by the sm all vibrational frequency shift associated with complex formation. Com parisons are made between the two systems studied here that indicate t hat this anomalous rate is due to a near resonance between the energy available to the fragments after the photodissociation of the complex and the asymmetric stretch of the CO2 fragment. (C) 1996 American Inst itute of Physics.