9802803 Boninsegni This is a Research at Undergraduate Institutions (RUI) Award for a theoretical program consisting of numerical studies of Helium physisorption. Computer simulations of Helium adsorbed on alkali surfaces and on graphite will be performed using the Path Integral Monte Carlo (PIMC) method. Available, realistic interatomic potentials will be adopted to model the interaction among Helium atoms, as well as between Helium atoms and the substrate. Specific objectives of the proposed research effort will be the study of the physical properties of a 4He adsorbate on the surface of alkali metals, as well as on a graphite substrate. The unifying theme of this research is the topic of physisorption, of great interest in condensed matter physics, and one where relatively little numerical simulation has been performed so far. This research is also expected to offer novel insight into such fundamental theoretical issues as phase transitions in reduced dimensions and monolayer superfluidity. The PIMC method is arguably the most powerful numerical tool currently available to calculate thermodynamic properties of quantum many-body systems directly from a microscopic Hamiltonian. The use of this technique in this research can afford quantitative predictions for a variety of adsorption phenomena involving differently attractive substrates and a quantum adsorbate; thus, it will help in the interpretation of several ongoing experiments involving Helium adsorption. %%% This is a Research at Undergraduate Institutions (RUI) Award to support a program of numerical simulation of the adsorption of Helium on various substrates including graphite. The numerical simulations will support a number of experiments being done elsewhere. The simulations will also provide insight into phase transitions of adsorbates on surfaces and on monolayer superfluidity. ***
