One- and two-photon spectroscopy of highly excited states of alkali-metal atoms on helium nanodroplets

J Chem Phys. 2010 Oct 28;133(16):164502. doi: 10.1063/1.3500397.

Abstract

Alkali-metal atoms captured on the surface of superfluid helium droplets are excited to high energies (≈3 eV) by means of pulsed lasers, and their laser-induced-fluorescence spectra are recorded. We report on the one-photon excitation of the (n+1)p←ns transition of K, Rb, and Cs (n=4, 5, and 6, respectively) and on the two-photon one-color excitation of the 5d←5s transition of Rb. Gated-photon-counting measurements are consistent with the relaxation rates of the bare atoms, hence consistent with the reasonable expectation that atoms quickly desorb from the droplet and droplet-induced relaxation need not be invoked.