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.