STATISTICAL-MECHANICS OF A POSITRON IN A CLASSICAL FLUID

Although the equilibrium theory of classical fluids, simple and comple x, has reached the stage of routine accurate evaluation, this is hardl y the case for even the next microscopic step, that of a quantum parti cle in a classical fluid. In many chemical applications, the quantum p article is an electron, but positron annihilation experiments on therm alized positrons and orthopositronium atoms offer a wealth of informat ion to test our theoretical understanding of this general class of sys tems. Here, we investigate several ways in which the concepts behind c lassical techniques can be generalized to handle this prototypical qua ntum problem, in the overt quantum form as well as in the classical po lymer representation. Both integral equation and density functional fo rmats are studied and their qualitative characteristics examined.