This three-year award for U.S.-France cooperative research in condensed matter physics involves the research groups of Oscar E. Vilches of the University of Washington and Michel Bienfait of the University of Marseille. The award provides travel support and living expenses to Dr. Vilches' graduate students. The objective of their research is to investigate the freezing (fractionation) and separation in adsorped hydrogen monolayers by performing neutron and X-ray scattering measurements at LLB-Saclay and at the new European Synchrotron Radiation Facility, and at ILL in Grenoble. The project takes advantage of French expertise and provides access to unique facilities located in France.