STRUCTURE OF 1-NAPHTHOL-WATER CLUSTERS STUDIED BY IR DIP SPECTROSCOPYAND AB-INITIO MOLECULAR-ORBITAL CALCULATIONS

The IR spectrum of cis-1-naphthol, trans-1-naphthol, and 1-naphthol .( H2O)(n) (n = 1-3) clusters has been measured by the LR dip spectroscop y in a supersonic jet. The spectra show clear vibrational structures o f the monomers and the clusters in the energy region from 3000 to 3800 cm(-1). Observed vibrational transitions are assigned to the OH stret ching vibrations of l-naphthol and waters in the clusters. The size de pendence of the IR bands and the cluster geometries are analyzed by us ing the ab initio MO method at the MP2/6-31G level. From the compariso n between the observed and calculated IR spectra, we have concluded th at the l-naphthol acts as the proton donor and a cyclic hydrogen-bond network is formed in the n = 2 and 3 clusters.