title: Photodissociation of an Internally Cold Beam of CH^{+} Ions in a Cryogenic Storage Ring.
abstract: We have studied the photodissociation of CH^{+} in the Cryogenic Storage Ring at ambient temperatures below 10 K. Owing to the extremely high vacuum of the cryogenic environment, we were able to store CH^{+} beams with a kinetic energy of ∼60  keV for several minutes. Using a pulsed laser, we observed Feshbach-type near-threshold photodissociation resonances for the rotational levels J=0-2 of CH^{+}, exclusively. In comparison to updated, state-of-the-art calculations, we find excellent agreement in the relative intensities of the resonances for a given J, and we can extract time-dependent level populations. Thus, we can monitor the spontaneous relaxation of CH^{+} to its lowest rotational states and demonstrate the preparation of an internally cold beam of molecular ions.
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: A P
authors.initials: AP
authors.lastname: O'Connor
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Becker
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Blaum
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.|Institut für Physik, Ernst-Moritz-Arndt Universität, 17487 Greifswald, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Breitenfeldt
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: George
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Göck
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Grieser
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Grussie
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: E A
authors.initials: EA
authors.lastname: Guerin
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: von Hahn
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Hechtfischer
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Herwig
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Karthein
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Krantz
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Kreckel
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Lohmann
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Meyer
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: P M
authors.initials: PM
authors.lastname: Mishra
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Novotný
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Repnow
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Saurabh
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.|Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Schwalm
authors.affiliation: Institut für Atom- und Molekülphysik, Universität Gießen, 35392 Gießen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Spruck
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Sunil Kumar
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Vogel
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Wolf