Spectroscopy and dynamics of Al atoms solvated in superfluid helium nanodroplets

The laser-induced fluorescence excitation spectrum in the vicinity of the 3(2)D <-- 3(2)P transition of Al atoms solvated in superfluid helium nanodroplets has been measured. While this transition has not been studied in bulk liquid helium, the observed blue shifts and line broadenings, compared with other transitions for which such measurements do exist, allow us to conclude that Al atoms reside in the interior of the helium droplet. The observed transition shows a splitting that we attribute to quadrupole-like deformations of the cavity formed in the helium droplet around the Al atom. Time-resolved studies of wavelength-selected emission from solvated Al atoms excited to the 3(2)D state reveal a rapid (less than or equal to 50 ps) and seemingly total nonradiative population transfer to the 4(2)S state, the decay of which is found to account for all of the emission and to have a lifetime (6.4 +/- 0.1 ns) that matches that of gas-phase Al.