Mass analyzed threshold ionization spectra of phenol…Ar2: Ionization energy and cation intermolecular vibrational frequencies

Abstract

The phenol+…Ar2 complex has been characterized in a supersonic jet by mass analyzed threshold ionization (MATI) spectroscopy via different intermediate intermolecular vibrational states of the first electronically excited state (S1). From the spectra recorded via the S100 origin and the S1βx intermolecular vibrational state, the ionization energy (IE) has been determined as 68 288 ± 5 cm-1, displaying a red shift of 340 cm-1 from the IE of the phenol+ monomer. Well-resolved, nearly harmonic vibrational progressions with a fundamental frequency of 10 cm-1 have been observed in the ion ground state (D0) and assigned to the symmetric van der Waals (vdW) bending mode, βx, along the x axis containing the C-O bond. MATI spectra recorded via the S1 state involving other higher-lying intermolecular vibrational states (σ 1s, β 3x, σ 1s β 1x, σ 1 s β 2 x) are characterized by unresolved broad structures. © the Owner Societies.