title: Ultrafast X-ray Auger probing of photoexcited molecular dynamics.
abstract: Molecules can efficiently and selectively convert light energy into other degrees of freedom. Disentangling the underlying ultrafast motion of electrons and nuclei of the photoexcited molecule presents a challenge to current spectroscopic approaches. Here we explore the photoexcited dynamics of molecules by an interaction with an ultrafast X-ray pulse creating a highly localized core hole that decays via Auger emission. We discover that the Auger spectrum as a function of photoexcitation--X-ray-probe delay contains valuable information about the nuclear and electronic degrees of freedom from an element-specific point of view. For the nucleobase thymine, the oxygen Auger spectrum shifts towards high kinetic energies, resulting from a particular C-O bond stretch in the ππ* photoexcited state. A subsequent shift of the Auger spectrum towards lower kinetic energies displays the electronic relaxation of the initial photoexcited state within 200 fs. Ab-initio simulations reinforce our interpretation and indicate an electronic decay to the nπ* state.
authors: PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: B K
authors: BK
authors: McFarland
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: J P
authors: JP
authors: Farrell
authors: PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: S
authors: S
authors: Miyabe
authors: Dipartimento di Chimica, Biologia e Biotecnologie, Universita di Perugia, and ISTM-CNR, 06123 Perugia, Italy.
authors: F
authors: F
authors: Tarantelli
authors: Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, California 94720, USA.
authors: A
authors: A
authors: Aguilar
authors: 1] Physics Department, Western Michigan University, Kalamazoo, Michigan 49008, USA [2].
authors: N
authors: N
authors: Berrah
authors: LCLS, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: C
authors: C
authors: Bostedt
authors: LCLS, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: J D
authors: JD
authors: Bozek
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: P H
authors: PH
authors: Bucksbaum
authors: LCLS, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: J C
authors: JC
authors: Castagna
authors: LCLS, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: R N
authors: RN
authors: Coffee
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: J P
authors: JP
authors: Cryan
authors: Physics Department, Western Michigan University, Kalamazoo, Michigan 49008, USA.
authors: L
authors: L
authors: Fang
authors: 1] Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden [2].
authors: R
authors: R
authors: Feifel
authors: PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: K J
authors: KJ
authors: Gaffney
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: J M
authors: JM
authors: Glownia
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Department of Chemistry, Stanford University, Stanford, California 94305, USA.
authors: T J
authors: TJ
authors: Martinez
authors: Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden.
authors: M
authors: M
authors: Mucke
authors: Physics Department, Western Michigan University, Kalamazoo, Michigan 49008, USA.
authors: B
authors: B
authors: Murphy
authors: PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: A
authors: A
authors: Natan
authors: Physics Department, Western Michigan University, Kalamazoo, Michigan 49008, USA.
authors: T
authors: T
authors: Osipov
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: V S
authors: VS
authors: Petrović
authors: LCLS, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: S
authors: S
authors: Schorb
authors: 1] Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin, Germany [2].
authors: Th
authors: T
authors: Schultz
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: L S
authors: LS
authors: Spector
authors: LCLS, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: M
authors: M
authors: Swiggers
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: I
authors: I
authors: Tenney
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: S
authors: S
authors: Wang
authors: 1] PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA [2] Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: J L
authors: JL
authors: White
authors: LCLS, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: W
authors: W
authors: White
authors: PULSE Institute, SLAC National Accelerator Laboratory, 2575, Sand Hill Road, Menlo Park, California 94025, USA.
authors: M
authors: M
authors: Gühr