10min:

C. CALLEGARI, J. HIGGINS, J. REHO, K. K. LEHMANN AND G. SCOLES, Chemistry Department, Princeton University, Princeton, NJ 08544.

Large He clusters (containing up to 10⁴ atoms) have been employed as a substrate to produce Na-(H₂)_n (n<10) complexes, making use of the pick-up technique. Laser Induced Fluorescence and Beam Depletion are used to spectroscopically investigate such complexes in the frequency region of Na D lines. A strong exponential decay of the total amount of collected fluorescence is observed as a function of H₂ pressure in the pick-up region, while Beam Depletion Spectra intensities are virtually unaffected, thus demonstrating the high quenching efficiency of H₂. Spectra are then compared to those of Na atoms on pure He or H₂ clusters. Interestingly, spectra of Na-(H₂)_n complexes show spectral features similar to those of Na on pure H₂ clusters only with smaller shifts with respect to the D lines position. Time resolved measurements are currently being taken and will be presented at the meeting.