hf level of ab initio calculations with basis-set 6-31g including full counterpoise correction hasbeen applied to compute the asphis potential with the ser and hisser potential with the asp inasphisser trimer. the potential energy surface has a minimum of -16.765 kcal/mol in r1=1.912nm and r2=2.719 nm. the optimum computed curves for two interactions were fitted withintermolecular pair potentia...

We derive path-integral expressions for the second and third virial coefficients of monatomic quantum gases. Unlike previous work that considered only Boltzmann statistics, we include exchange effects (Bose-Einstein or Fermi-Dirac statistics). We use state-of-the-art pair and three-body potentials to calculate the third virial coefficient of (3)He and (4)He in the temperature range 2.6-24.5561 ...

A new method is proposed for a quantitative investigation of interchain interactions in a poor solvent within the framework of a Lifshits type mean-field approximation. Density distributions and interaction free energy for two globules equilibrated at an arbitrary distance ( from each other are calculated. The corresponding pair virial coefficient and coexistence binodal curve in the second vir...

Abstract. Quantum effects in statistical mechanics are important when the thermal wavelength is of the order of, or greater than, the mean interatomic spacing. This is examined at depth taking the example of a hard-sphere Boltzmann gas. Using the virial expansion for the equation of state, it is shown that the interaction energy of a classical hard-sphere gas is exactly zero. When the (second) ...

The existence of interactions among the particles of a system is a common situation in statistical physics, for instance in real gases or weak liquid solutions. On the one hand, these interactions limit the range of applicability of the ideal equation of state. On the other hand, they give rise to a whole new class of exciting phenomena, such as thermodynamic instability and metastability, phas...