Vibrationally- and rotationally-resolved photoelectron imaging of cryogenically-cooled SbO₂^–

Abstract

We report a temperature-controlled photoelectron imaging study of SbO₂^–, produced from a laser vaporisation source and cooled in a cryogenic 3D Paul trap. Vibrationally resolved photoelectron spectra are obtained for the ground state detachment transition, yielding the bending frequencies for both SbO₂ and SbO₂^–. Franck-Condon simulations also allow the estimate of the vibrational temperature of the trapped SbO₂^– anion. A near-threshold spectrum of SbO₂^– at a photon energy of 3.4958 eV reveals partially resolved rotational structure for the 0–0 transition, which yields an accurate electron affinity of 3.4945 ± 0.0004 eV for SbO₂. The rotational simulation also yields an estimated rotational temperature of the trapped ions.

GRAPHICAL ABSTRACT

KEYWORDS:

• Photoelectron imaging
• cryogenic cooling
• ion traps
• photoelectron spectroscopy
• antimony oxide

Acknowledgements

This paper is dedicated to the memory of Prof. Dieter Gerlich. One of us (PI: L.S.W.) would like to thank Prof. Dieter Gerlich for his support and discussion when he was developing the first cryogenically-cooled 3D Paul trap [6,7]. When the PI was preparing the design of this instrument, he invited Dieter to Richland, Washington for consultation. Much to his surprise, Dieter told him that the 3D Paul trap would not work and instantly offered the PI his 22-pole ion trap design! After the PI realised that the dimension of Dieter’s 22-pole ion trap was similar to the commercially available Paul trap, he went ahead with his original plan, reasoning that if it did not work he could easily switch to the 22-pole trap design. Dieter even connected the PI to have a decommissioned 22-pole ion trap from Taiwan shipped to the PI then at Richland, Washington, which was eventually shipped back to Dieter in Germany after the 3D Paul trap design was shown to be effective in cooling trapped ions from an electrospray ion source [6–11].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Science Foundation(NSF) under Award No. CHE-2053541. GSK was partially supported by a NASA Rhode Island Space Science Grant Award No. 80NSSC20M0053.