AUTOIONIZING VIBRONIC RYDBERG SERIES IN 2-COLOR, 2-PHOTON ION YIELD SPECTRA OF JET-COOLED BENZENE AND THE BENZENE-AR COMPLEX

The high-sensitivity technique consisting of molecular jet cooling and two-color, two-photon ionization spectroscopy with mass-selected detection in a time-of-flight mass spectrometer is used to investigate high-lying autoionizing Rydberg vibronic levels in benzene and the benzene-Ar complex. In particular, a long Rydberg series (from n = 11 to 21 and delta congruent-to -0.10) is characterized, converging to the 1 mode level of the ground-state cation, when benzene or the benzene-Ar complex is initially excited in their S16(1)1(1) respective level. This series fairly fits and greatly extends the series (3 less-than-or-equal-to n less-than-or-equal-to 7, delta = -0.11) previously characterized by Whetten et al. in their 2 + 1 REMPI study (J. Chem. Phys. 1985, 82, 1115) and assigned to a nd1 Rydberg state.