Rotationally cold OH${}^{-}$ ions in the cryogenic electrostatic ion-beam storage ring DESIREE

Abstract

We apply near-threshold laser photodetachment to characterize the rotational quantum level distribution of OH${}^{-}$ ions stored in the cryogenic ion-beam storage ring, DESIREE, at Stockholm University. We find that the stored ions relax to a rotational temperature of 13.4$\pm$0.2 K with 94.9$\pm$0.3 % of the ions in the rotational ground state. This is consistent with the storage ring temperature of 13.5$\pm$0.5 K as measured with eight silicon diodes, but in contrast to all earlier studies in cryogenic traps and rings where the rotational temperatures were always much higher than those of the storage devices at their lowest temperatures. Furthermore, we actively modify the rotational distribution through selective photodetachment to produce an OH${}^{-}$ beam where 99.1$\pm$0.1 % of approximately one million stored ions are in the $J$=0 rotational ground state.

References in corpus (8)

• Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate
• First storage of ion beams in the Double Electrostatic Ion-Ring Experiment - DESIREE
• The Cryogenic Storage Ring CSR
• Internal state thermometry of cold trapped molecular anions
• Radiative rotational lifetimes and state-resolved relative detachment cross sections from photodetachment thermometry of molecular anions in a cryogenic storage ring
• Spontaneous decay of small copper cluster anions Cu${}_n^{-}$, $n=3-6$ on long time scales
• Radiative lifetimes of the bound excited states of ${\text{Pt}}^{-}$
• The lifetime of the bound excited level in Ni${}^{-}$

Cited by in corpus (8)

• Evidence for two-electron processes in the mutual neutralization of O- with O+ and N+ at Subthermal Collision Energies
• Ultraslow radiative cooling of C${}_n^{-}$ ($n=3-5$)
• Decays of excited silver cluster anions Ag${}_n$, $n=4$ to $7$, in DESIREE
• Dianion diagnostics in DESIREE: High-sensitivity detection of ${\text{C}}_n^{2-}$ from a sputter ion source
• Mutual neutralization of C${}_{60}^{+}$ and C${}_{60}^{-}$ ions: Excitation energies and state-selective rate coefficients
• Status of the Laser Spectroscopy and Merged-beam Experiments at RICE
• Stability of C${}_{59}$ Knockout Fragments from Femtoseconds to Infinity
• Laser-probing the rotational cooling of molecular ions by electron collisions