title: Cooling dynamics of photoexcited C6(-) and C6H(-).
abstract: We report conclusive evidence of an efficient cooling mechanism via the electronic radiative transitions of hot small molecular anions isolated in vacuum. We stored C6(-) and C6H(-) in an ion storage ring and observed laser-induced electron detachment with delays up to several milliseconds. The terminal hydrogen atom caused a drastic change in the decay profiles. The decay of photoexcited C6H(-) is slow and nonexponential, which can be explained by depletion cooling, whereas that for C6(-) occurs extremely fast, on a time scale below 0.1 ms and can only be explained by electronic radiative cooling via low-lying electronic excited states.
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Ito
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Furukawa
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tanuma
authors.affiliation: Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Matsumoto
authors.affiliation: Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shiromaru
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan and Quantum Science and Engineering Center, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Majima
authors.affiliation: Atomic, Molecular and Optical Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Goto
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan and Atomic, Molecular and Optical Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Azuma
authors.affiliation: Department of Physics, University of Gothenburg, 41296 Gothenburg, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Hansen