Weakly bound ion-neutral complexes for generating ultracold molecules

Ultracold atoms and molecules are the fundamental building blocks of quantum science, yet the primary technique of generating these particles — laser cooling — remains impractical for a wide variety of species. We present  a broadly applicable technique for generating ultracold molecules from the near-threshold photodissociation of sympathetically cooled, weakly bound ion-molecule complexes. These complexes, formed through long-range electrostatic interactions between a metal ion and a polarizable atom/molecule, exhibit bond energies on the order of 0.01–0.1 eV . As a first step towards this goal, we describe the production of cold (T < 10 K) ion-molecule complexes by mixing ablated metal ions into a supersonic molecular beam seeded with the target molecule^[1]. Additionally, we outline our progress towards the loading of these cold complexes into an ion trap. Finally, we discuss optimization strategies — such as tuning ablation laser energy, metal source composition, and gas pulse parameters — to enhance complex formation efficiency.

[1]  Powers, D. E., S. G. Hansen, M. E. Geusic, A. C. Puiu, J. B. Hopkins, T. G. Dietz, M. A. Duncan, P. R. R. Langridge-Smith, & R. E. Smalley, “Supersonic metal cluster beams: laser photoionization studies of copper cluster (Cu₂),” J. Phys. Chem. 86, 2556-2560 (1982). DOI:10.1021/j100211a002.