Two-photon spectroscopy of styrene: detection of the 3p Rydberg states

Resonance enhanced multiphoton ionization spectroscopy, (2C1) REMPI, has been employed in jet cooled styrene vapors for the detection of Rydberg states. A resonance appears at 50,484 cmK1 and is interpreted as a 3p)HOMO Rydberg transition (dZ0.52). The 3s state was not detected in the REMPI experiments. The comparison of the experimental spectrum of styrene, in the energy region 5.3–6.6 eV, with two theoretical works from the literature (CASPT2 and SAC-CI) shows that the CASPT2 results are very close to the experiment and more reliable than the SAC-SI. q 2004 Elsevier B.V. All rights reserved.