The Assembly and Spectroscopic Interrogation of Hydrogen Clusters in Helium Droplets

University Of Southern California, Los Angeles CA

Investigators

Abstract

In this project funded by the Experimental Physical Chemistry Program of the Chemistry Division, Vilesov will investigate fundamental properties of hydrogen molecules and clusters trapped in ultracold helium droplets. The work consists of two parts. In the first, the focus is on H2, D2, and HD molecules clustered to chromophores with different properties. The second part will be devoted to the study of neat hydrogen clusters, special attention being given to those in the size range below 30 molecules. Infrared and CARS spectroscopy will be employed in these investigations. Research on molecules and clusters entrapped in ultracold droplets of liquid helium provides new information on their behavior not available with conventional techniques. Not only do the trapped species vibrate, but they also rotate in the droplets, which indicates that the interaction between the trapped species and the embedding bath is minimal. The slight changes in the rotational energies relative of those that pertain to gaseous molecules allow a quantitative assessment of the forces that bind the molecules into the droplets.