Electronic spectroscopy of 1-naphthol/solvent clusters 1-NpOH/S, S=H2O, ar and N2

The electronic structure of trans-1-naphthol solvated with H2O, Ar and N-2 was investigated using multiphoton ionization spectroscopy and spectral hole burning. The hole burning spectra aided in the identification of several new intermolecular vibrations in the cluster with one water molecule, and showed that in the REMPI spectrum of the cluster with a single Ar only one isomer was present. Several low-frequency vibrational bands were observed and assigned. The red-shifts of the S-1 <-- S-0 transition are surprisingly different from those measured for phenol and 2-naphthol clusters. The experiments were supported by electronic structure calculations, yielding geometries and binding energies of the clusters. The results obtained for the 1-naphthol/N-2 cluster were particularly surprising. Computations indicate a pi-bound structure that is more stable than the H-bound structure. The experimentally observed small red-shift upon excitation seems to support this picture. (C) 2004 Elsevier B.V. All rights reserved.