Accession Number : ADA266060

Title :   Quantum Dynamics of Helium Clusters

Descriptive Note : Final rept. Mar 1989-Mar 1993


Personal Author(s) : Whaley, K B

Full Text :

Report Date : Mar 1993

Pagination or Media Count : 44

Abstract : Our study of helium clusters was motivated by the desire to understand the scaling of the unusual properties of bulk 4He, a quantum liquid, in finite size systems as one goes from the macroscopic regime to the regime of molecular dimensions. This is fully in the spirit of general cluster research, namely to develop our understanding of how the transition from molecular to bulk systems (or vice versa) is reflected in the internal structure and dynamics of finite size aggregates. The unique feature of helium is its dominant quantum behavior, resulting from a low mass and weak interatomic binding energy. Clusters of helium are therefore very weakly bound van der Waals species, whose properties were expected to be dominated by zero point delocalization effects. During this grant period, we devoted our attention exclusively to clusters of 4He, which are bose systems. These are more strongly bound than the fermionic species 3He sub N, and are also easier and cheaper to study experimentally. Furthermore, analogy with the bulk behavior suggests that any superfluid effects if present will occur at considerably higher and therefore experimentally more readily accessible temperatures for the 4He species. In addition to the helium clusters, we also applied our Monte Carlo techniques to clusters of molecular hydrogen, which for J=0 are also Bose clusters. These are more strongly bound than clusters of helium, yet are still very delocalized by chemical standards and offer an intriguing possibility of a new superfluid


Subject Categories : Inorganic Chemistry
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE