title: Vibrational scattering anisotropy generated by multichannel quantum interference.
abstract: Based on angularly and vibrationally resolved electron spectroscopy measurements in acetylene, we report the first observation of anomalously strong vibrational anisotropy of resonant Auger scattering through the C 1s→π* excited state. We provide a theoretical model explaining the new phenomenon by three coexisting interference effects: (i) interference between resonant and direct photoionization channels, (ii) interference of the scattering channels through the core-excited bending states with orthogonal orientation of the molecular orbitals, (iii) scattering through two wells of the double-well bending mode potential. The interplay of nuclear and electronic motions offers in this case a new type of nuclear wave packet interferometry sensitive to the anisotropy of nuclear dynamics: whether which-path information is available or not depends on the final vibrational state serving for path selection.
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France.
authors.forename: Catalin
authors.initials: C
authors.lastname: Miron
authors.forename: Victor
authors.initials: V
authors.lastname: Kimberg
authors.forename: Paul
authors.initials: P
authors.lastname: Morin
authors.forename: Christophe
authors.initials: C
authors.lastname: Nicolas
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Kosugi
authors.forename: Sergey
authors.initials: S
authors.lastname: Gavrilyuk
authors.forename: Faris
authors.initials: F
authors.lastname: Gel'mukhanov