title: Improved determination of structural changes of 2-pyridone-(H2O)1 upon electronic excitation.
abstract: The change of the 2-pyridone-water cluster (2PYH(2)O) structure upon electronic excitation is determined by a Franck-Condon analysis of the intensities in the fluorescence emission spectra obtained via excitation of three different vibronic bands as well as a structural fit based on the rotational constants of eight isotopomers that have been reported by Held and Pratt (J. Am. Chem. Soc., 1993, 115, 9708]. A total of 93 emission band intensities were fit, together with the changes of rotational constants of 8 isotopomers. The geometry change upon electronic excitation to the pipi* state can be described by a strong and unsymmetrical elongation of the hydrogen bonds, a contraction of the OH bond involved in the cyclic cluster arrangement, and an unsymmetrical ring deformation. The resulting geometry changes are interpreted on the basis of ab initio calculations.
authors.affiliation: Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Brause
authors.forename: Michael
authors.initials: M
authors.lastname: Schmitt
authors.forename: Karl
authors.initials: K
authors.lastname: Kleinermanns
mesh_terms: D003198:Computer Simulation; D004583:Electrons; D008958:Models, Molecular; D015394:Molecular Structure; D011728:Pyridones / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D011728:Pyridones; D014867:Water; C017679:2-hydroxypyridine