Adsorption Structure of 3He Monolayer Solid Film on Grafoil

The adsorption structure of 3 He submonolayer solid film on a, Grafoil Surface is considered. The adsorption energies of some supposed structures are calculated by the path integral Monte Carlo simulations. According to these calculations the evolution of the adsorption structure is discussed. Two structural, phase transitions are predicted there. The phase boundaries coincide with the specific features in the results of heat-capacity measurements. The commensurate - incommensurate phase transition seems responsible for the sudden ferromagnetic peak of the exchange frequency.