Thermodynamics of boson liquid films

Theoretical studies of films of liquid ⁴He adsorbed to strong, plane substrates indicate that the growth of such films occurs through a sequence of first-order phase transitions -"layering transitions" - which are a direct consequence of the short-range, hard-core like interaction between individual helium atoms. The present work examines the effects of temperature on these transitions. At given temperatures, the spinodal points and phase coexistence boundaries are determined for the transitions. Increasing the temperature tends to decrease the coverage span of the transition regions, signalling the possible existence of a critical point terminating the two-phase equilibrium.