Two-photon spectroscopy in helium (A)

D. Bakalov, Igor V. Puzynin, Т. П. Пузынина +1 more

Scott Bergeson, K. G. H. Baldwin, Thomas B. Lucatorto +3 more

M. P. McCann, C. H. Chen, Marvin G. Payne

Andreas Przystawik, Paul Radcliffe, Sebastian Göde +2 more

Silver dimers embedded in ultracold helium nanodroplets are ionized by two-photon excitation via a strong resonance which extends from 3.85 eV up to 4.1 eV. The corresponding photoelectron spectra reveal that the ionization threshold is shifted by more than 1.4 eV towards lower values when compared to the gas phase. This gives strong evidence that weakly bound dimers in the lowest lying triplet state are present, thus enabling convenient spectroscopy of the triplet Ag 2 . A comparison with predictions from theory allows an assignment of the structure in the spectra. The successful identification of triplet silver dimers embedded in helium droplets shows exemplarily that the formation of such weakly bound systems is not restricted to surface locations as with the alkalis, but represents a general feature of the ultracold helium droplet environment.

H. W. van der Hart, Feng Liang

A. Dalgarno