VIBRATIONAL PREDISSOCIATION SPECTROSCOPY OF BINARY COMPLEXES INVOLVING BENZENE

The vibrational predissociation spectra of $(C_{6}H_{6})_{2'} (C_{6}H_{6})-Ar$ and $C_{6}H_{6}$-Xe have been measured in the 3000 to $3100 cm^{-1}$ region using a $LiNbO_{3}$ optical parametric oscillator (OPO) and a molecular beam apparatus equipped with a mass-spectrometer detection system. The OPO linewidth of $0.6 cm^{-1}$ is sufficiently narrow to resolve two components in each $(C_{6}H_{6})_{2}$ vibrational band. The Ar and Xe complexes have only one component. The data indicate each component can be assigned to one of the benzene molecules in the dimer complex. The structural implications of these results will be discussed. The predissociation linewidths of the $(C_{6}H_{6})_{2}$ components, $Ar-C_{6}H_{6}$ and $Xe-C_{6}H_{6}$ are $\\sim 2.0 cm^{-1}$. The rotational band contours will be discussed along with upper state lifetimes.