Quantum-Mechanical Second Virial Coefficient at High Temperatures

An expression is obtained for the quantum-mechanical second virial coefficient in the form of an inverse Laplace transform of the logarithmic derivative of the Jost function. This form is useful for the calculation of the direct part of the virial coefficient at high temperatures in cases where the Wigner-Kirkwood expansion breaks down. Explicit calculations are presented for hard spheres, the square-well potential, and the square-well potential with a hard core.