title: Photodetachment of cold OH- in a multipole ion trap.
abstract: The absolute photodetachment cross section of OH- anions at a rotational and translational temperature of 170 K is determined by measuring the detachment-induced decay rate of the anions in a multipole radio-frequency ion trap. In comparison with previous results, the obtained cross section shows the importance of the initial rotational-state distribution. Using a tomography scan of the photodetachment laser through the trapped ion cloud, the derived cross section is model-independent and thus features a small systematic uncertainty. The tomography also yields the column density of the OH- anions in the 22-pole ion trap in good agreement with the expected trapping potential of a large field free region bound by steep potential walls.
authors.affiliation: Physikalisches Institut, Universität Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Trippel
authors.forename: J
authors.initials: J
authors.lastname: Mikosch
authors.forename: R
authors.initials: R
authors.lastname: Berhane
authors.forename: R
authors.initials: R
authors.lastname: Otto
authors.forename: M
authors.initials: M
authors.lastname: Weidemüller
authors.forename: R
authors.initials: R
authors.lastname: Wester