The vibronic spectra of the first excited singlet state (S1) and the cation spectra of the ground state of the cation (D0) of jet-cooled cyclopropylbenzene (CPB) were investigated using resonance-enhanced multiphoton ionization (REMPI) and photoelectron velocity-map imaging techniques, respectively. The vibronic spectra indicated the existence of only the bisected conformer, a finding corroborated by quantum chemical calculations. The S0 → S1 electronic transition originated at 36,858.5 cm−1, with an adiabatic ionization energy of 66,846 ± 15 cm−1. Vibrational levels in both states were assigned with the assistance of theoretical geometry optimization and frequency calculations. These experimental spectra and theoretical calculations provided valuable insights into the structural and vibrational characteristics of CPB in its excited and cationic states.
Hua et al. (Thu,) studied this question.