Quantum Corrections to the Second Virial Coefficient, with an Application to the Hard-Core-Plus-Square-Well Potential at High Temperatures

A new formulation of the second-virial-coefficient problem, particularly useful for the computation of the direct second virial coefficient $B_{\mathrm{dir}}$ at high temperatures and as good as the phase-shift formulation at low temperatures, is given. High-temperature asymptotic expansions of $B_{\mathrm{dir}}$ for hard-core and hard-core-plus-square-well potentials are calculated. The exchange second virial coefficient for a hard-core-plus-square-well potential at high temperatures is investigated.