title: Probing keto-enol tautomerism using photoelectron spectroscopy.
abstract: We theoretically investigate the mechanism of tautomerism in the gas-phase acetylacetone molecule. The minimum energy path between the enolone and diketo forms has been computed using the Nudged-Elastic Band (NEB) method within the density-functional theory (DFT) using the projector augmented-wave method and generalized gradient approximation in Perdew-Wang (PW91) parametrization. The lowest transition state as well as several intermediate geometries between the two stable tautomers have been identified. The outer-valence ionization spectra for all determined geometries have been computed using the third-order non-Dyson algebraic diagrammatic construction technique. Furthermore, the oxygen core-shell ionization spectra for these geometries have been obtained using DFT and the Becke three-parameter Lee-Yang-Parr (B3LYP) functional. It is shown that all spectra depend strongly on the geometries demonstrating the possibility of following the proton-transfer dynamics using photoelectron spectroscopy in pump-probe experiments.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement, F-75005, Paris, France. Nicolas.Sisourat@upmc.fr.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Capron
authors.forename: Bastien
authors.initials: B
authors.lastname: Casier
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sisourat
authors.forename: Maria Novella
authors.initials: MN
authors.lastname: Piancastelli
authors.forename: Marc
authors.initials: M
authors.lastname: Simon
authors.forename: Stéphane
authors.initials: S
authors.lastname: Carniato