title: Mass-analyzed threshold ionization spectroscopy of the rotamers of p-n-propylphenol cations and configuration effect.
abstract: Two-color resonant two-photon mass-analyzed threshold ionization (MATI) spectroscopy was used to record the vibrationally resolved cation spectra of the selected rotamers of p-n-propylphenol. The adiabatic ionization energies of the trans, gauche-A, and gauche-B rotamers are determined to be 65 283+/-5, 65 385+/-5, and 65 369+/-5 cm(-1), which are less than that of phenol by 3342, 3240, and 3256 cm(-1), respectively. This suggests that the n-propyl substitution causes a greater degree in lowering the energy level in the cationic than the neutral ground state. Analysis on the MATI spectra of the selected rotamers of p-n-propylphenol cation shows that the relative orientation of the p-n-alkyl group has little effect on the in-plane ring vibrations. However, the low-frequency C(3)H(7) bending vibrations appear to be active only for the two gauche forms of the cation.
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Changyong
authors.initials: C
authors.lastname: Li
authors.forename: Jung Lee
authors.initials: JL
authors.lastname: Lin
authors.forename: Wen Bih
authors.initials: WB
authors.lastname: Tzeng