Picosecond (or less) pulsed excitation of the reactant, leading toĪmbiguities concerning the nature of the prepared state. Of the ESPT reaction was monitored by the appearance of a redshifted emission of the product on short time scales, following Of 7AI.6 However, in all of these cases except the first, the course Relevant recen t experiments include studies of 2-(20 -hydroxyphenyl)5-phenyloxazole (HPPO),3 the 7-azaindole (7AI) dimer,4 methanol complexes of 7-hydroxyquinoline (HYQ),5 and water complexes Pioneering study of Herek, et al.2 on methyl salicylate (MS). To as excited-state proton transfer (ESPT) reactions,1 since the Interest remains high in reactions of this type, loosely referred Which makes possible the measurement of the rate of an excitedstate hydrogen atom transfer reaction in the isolated molecule,įree of the perturbations of external solvent molecules. Spectrum of syn-2-(20 -pyridyl)pyrrole (2PP) in the gas phase, SECTION: Dynamics, Clusters, Excited StatesĮ wish to report the observation of homogeneous lineīroadening in the high-resolution fluorescence excitation The rate of the ESPT reaction isĮnhanced by more than an order of magnitude with simultaneousĮxcitation of a 144 cm! in-plane vibrational mode. Transfer of the proton is inhibited by an unfavorably oriented dipole Apparently, excitation of the S1 state moves electronicĬharge from the pyrrole ring to the pyridine ring, but the simultaneous Measured by the homogeneous line broadening that is observed in its Planar molecule in both the ground (S0) and first excited (S1)Įlectronic states, and that the S1 state undergoes a relatively slowĮxcited-state proton transfer (ESPT) reaction when excited by light, as Analyses of these data show that the syn conformer of 2PP is a Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52 01-224 Warsaw, PolandĪBSTRACT: Microwave and UV excitation spectra of 2-(20 -pyridyl)pyrrole (2PP) have been recorded at high resolution in the gas Pratt*ĭepartment of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United Statesĭepartment of Chemistry, University of Houston, Houston, Texas 77204, United States Fleisher, Vanesa Vaquero-Vara, and David W. The Nanosecond Time Scale in the Gas Phase Excited-State Proton Transfer in syn-2-(20 -Pyridyl)pyrrole Occurs on