title: Direct observation of collective modes coupled to molecular orbital-driven charge transfer.
abstract: Correlated electron systems can undergo ultrafast photoinduced phase transitions involving concerted transformations of electronic and lattice structure. Understanding these phenomena requires identifying the key structural modes that couple to the electronic states. We report the ultrafast photoresponse of the molecular crystal Me4P[Pt(dmit)2]2, which exhibits a photoinduced charge transfer similar to transitions between thermally accessible states, and demonstrate how femtosecond electron diffraction can be applied to directly observe the associated molecular motions. Even for such a complex system, the key large-amplitude modes can be identified by eye and involve a dimer expansion and a librational mode. The dynamics are consistent with the time-resolved optical study, revealing how the electronic, molecular, and lattice structures together facilitate ultrafast switching of the state.
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany. Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Hayes
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany. Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Sercan
authors.initials: S
authors.lastname: Keskin
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany. Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Gastón
authors.initials: G
authors.lastname: Corthey
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany. JST-PRESTO, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8502, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Hada
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Kostyantyn
authors.initials: K
authors.lastname: Pichugin
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany. Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Marx
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany. Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Hirscht
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Shionuma
authors.affiliation: JST-PRESTO, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8502, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Onda
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Okimoto
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551, Japan. JST-CREST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Koshihara
authors.affiliation: Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Condensed Molecular Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Hengbo
authors.initials: H
authors.lastname: Cui
authors.affiliation: Condensed Molecular Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Mitsushiro
authors.initials: M
authors.lastname: Nomura
authors.affiliation: Condensed Molecular Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Yugo
authors.initials: Y
authors.lastname: Oshima
authors.affiliation: Condensed Molecular Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Majed
authors.initials: M
authors.lastname: Abdel-Jawad
authors.affiliation: Condensed Molecular Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Reizo
authors.initials: R
authors.lastname: Kato
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany. Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany. Departments of Chemistry and Physics, University of Toronto, Toronto, Ontario M5S 3H6, Canada. dwayne.miller@mpsd.mpg.de.
authors.forename: R J Dwayne
authors.initials: RJ
authors.lastname: Miller