High-lying Rydberg states and ionization energy of vinyl chloride studied by two-photon resonant ionization spectroscopy

High-lying Rydberg states of jet-cooled vinyl chloride at 9.3–10 eV are investigated using 2+1 resonance-enhanced multiphoton ionization spectroscopy. Four Rydberg series are observed and tentatively assigned as due to the transitions of π→ns, npσ, npπ, and nf Rydberg orbitals associated with quantum defects of 0.94, 0.89, 0.48, and 0.02, respectively. All of the four series converge to the same ionization energy limit corresponding to the ground state of vinyl chloride cation. The adiabatic ionization energy of vinyl chloride is determined to be 80 720±6 cm−1, in excellent agreement with previously reported values.