ELECTRONIC-SPECTRA OF JET-COOLED TROPOLONE-M(N)(N=1,2) CLUSTERS - MICROSCOPIC SOLVENT EFFECTS ON PROTON TUNNELING IN THE S-1 STATE

The S-1<--S-0 fluorescence excitation spectra of jet-cooled tropolone (TRN)-M(n) (M=Ar, Kr, Xe, N-2, CH4/CD4, C2H6, C3H8, CCl4; n=1,2) clusters have been measured in the wavelength region near the electronic origin to investigate the effects of van der Waals interactions on proton tunneling in the electronic excited S-1 state. The solvation of TRN with the rare gas atom(s) has small effect on the 0(0)(0) tunneling splitting, while the solvation with the molecule(s) considerably decreases the tunneling splitting. The decrease in the tunneling splittings of the TRN clusters has been explained by strong coupling of intermolecular vibration with intramolecular vibration of TRN, increasing the effective potential barrier height and/or tunneling distance. The anisotropy in the intermolecular interactions, and the configuration and number of solvent molecules are suggested to be important factors for the changes in the tunneling splitting. (C) 1995 American Institute of Physics.