Vibronic spectra of the allyl radical at 6—8 eV with resonance-enhanced multiphoton ionization technique

Abstract

The allyl radical was produced in molecular beam by pyrolysis of allyl iodide. The vibronic spectra from ground state to six new electronic states of the allyl radical at 6—8eV, π →3d xz , π →3d xy ,and π → ns ( n =4,6,7,8) were observed firstly with the aid of time-of-flight mass spectroscopy and resonance-enhanced multiphoton ionization technique. Vibrational progression of ν 7 (C 3 bend) with gross spacing of about 430 cm -1 was observed in ns Rydberg states. The adiabatic ionization potential of the allyl radical was obtained to be (65641 ± 20)cm -1 ((8.138 ± 0.002) eV) by fitting the term values of ns ( n =4,6,7,8)Rydberg states with Rydberg formula.