posted on 2015-06-18, 14:32authored byJ. Jeffs, N. A. Besley, A. J. Stace, Gautam Sarma, Ethan M. Cuynningham, Adrian Boatwright, Shengfu Yang, Andrew M. Ellis
Metal atoms have proved to be sensitive probes of the properties of superfluid helium nanodroplets. To date, all experiments on the doping of helium droplets have concentrated on the attachment of metal atoms in their ground electronic states. Here we report the first examples of metal atoms in excited states becoming attached to helium nanodroplets. The atoms in question are aluminum, and they have been generated by laser ablation in a metastable quartet state, which attaches to and remains on the surface of helium droplets. Evidence for a surface location comes from electronic spectra, which consist of very narrow absorption profiles that show very small spectral shifts. Supporting ab initio calculations show there to be an energy incentive for a metastable Al atom to remain on the surface of a helium droplet rather than move to the interior. The results suggest that helium droplets may provide a method for the capture and transport of metastable excited atomic and molecular species.
Funding
The authors would like to thank EPSRC and the
Leverhulme Trust for financial support. The Nuffield Foundation
is also thanked for providing a bursary to E. M. C.
History
Citation
Physical Review Letters 114, 233401
Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Chemistry