Observation of vibronically excited thioformaldehyde at 62,000-72,000 cm−1 by 1 + 1′ + 1′ resonance enhanced multiphoton ionization spectroscopy

Vibronically excited thioformaldehyde (H2CS) has been studied by two-color 1 + 1′ + 1′ resonance enhanced multiphoton ionization (REMPI) spectroscopy, in which the C˜ 1B2000 state of H2CS was selected as an intermediate state for the resonant excitation to high-lying electronic states at 62,000-72,000 cm−1. In light of the distinctive selection rules for the 1 + 1′ + 1′ REMPI and one-photon direct absorption transitions excited from the C˜1B2 and X˜1A1 states of H2CS, respectively, we have been able to identify 1 valence state (nπ, π*2), and 14 Rydberg states (n, 5s), (π, 4s), (n, 3dxz), (n, 3dyz), (n, 5pz), (n, 5px), (n, 5py), (n,4dz2), (n, 4dxz), (n, 4dyz), (n, 6s), (π, 4py), (n, 6pz), and (n, 6py), in this study.