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) clust ers have been measured in the wavelength region near the electronic or igin to investigate the effects of van der Waals interactions on proto n 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 sp litting, while the solvation with the molecule(s) considerably decreas es the tunneling splitting. The decrease in the tunneling splittings o f the TRN clusters has been explained by strong coupling of intermolec ular vibration with intramolecular vibration of TRN, increasing the ef fective potential barrier height and/or tunneling distance. The anisot ropy in the intermolecular interactions, and the configuration and num ber of solvent molecules are suggested to be important factors for the changes in the tunneling splitting. (C) 1995 American Institute of Ph ysics.