15min:

KIRILL E. KUYANOV, Department of Chemistry, University of Southern California, Los Angeles, CA 90089; MIKHAIL N. SLIPCHENKO, Department of Chemistry, Iowa State University, Ames, IA 50011; BOBBY KHALAJESTANI, RUSSELL SLITER AND ANDREY F. VILESOV, Department of Chemistry, University of Southern California, Los Angeles, CA 90089.

Neat H₂ clusters as well as H₂ clusters embedded in helium droplets have been obtained in a pulsed cryogenic nozzle beam expansion and studied via Coherent anti-Stokes Raman Scattering (CARS) technique. The motivation for these experiments is to spectroscopically observe superfluidity in molecular hydrogen clusters. Results on large hydrogen clusters of about 10⁴ molecules presented. We have studied the composition and structure of the clusters obtained from the H₂ gas with different concentrations of para -H₂ and ortho -H₂ molecules. CARS spectra indicate the enrichment in ortho -H₂ in the clusters.