10min:

MARTIN C. R. COCKETT, DARREN M. CHAPMAN, CAROLINE E. H. DESSENT, WOLF D. GEPPERT, STEPHEN R. HAINES, KLAUS MÜLLER-DETHLEFS AND MARK J. WATKINS, Department of Chemistry, University of York, Heslington, York, United Kingdom, YO1 5DD.

The vibrational spectrum of the [phenol·N₂]⁺ complex cation has been observed for the first time by high resolution two-colour threshold ionisation techniques (ZEKE-PFI spectroscopy and mass analysed threshold ionisation (MATI) spectroscopy). The spectra exhibit vibrational progressions in three modes, which have been assigned on the basis of \textslab initio\/ calculations, to the three intermolecular modes (in-plane bend ß' 35 cm^-1, wag \gamma' 113 cm^-1 and stretch ' 125 cm^-1). ZEKE and MATI spectra were acquired through different intermediate S₁ vibrational levels to aid the assignment of the vibrational structure in the cation spectra. Features were observed in the [phenol·N₂]⁺ MATI channel up to an ion internal energy of 1400 cm^-1 providing a lower bound for the dissociation energy of the cationic complex. Although the binding energy is weaker than the hydrogen bonded [phenol·water] cluster, it is considerably stronger than the van der Waals [phenol·Ar]⁺ complex suggesting an intermediate binding case characteristic of a combined charge-induced dipole / charge-quadrupole interaction.