Intermolecular excited-state proton transfer in clusters of 1-naphthol with water and with ammonia

The excited-state proton transfer reactions of 1-naphthol(H2O)(n) and 1-nap hthol(NH3)(n) clusters are compared. Both exisiting and new data suggest th at the two systems may react in strikingly different fashions, roughly corr esponding to non-adiabatic and adiabatic limiting cases, respectively. In w ater clusters, the reaction is kinetically limited by solvent motion, and t here is a strong dynamic interaction involving the water and two lowest ele ctronic excited states, which thereby invert. In ammonia clusters, the exci ted states appear to be premixed by the the stronger base, and the reaction may proceed in a rapid manner, resembling intracluster vibrational relaxat ion, with relatively little solvent reorganization.