Pair-pair correlations in simple fluids

Correlations in a fluid between pairs of spherically symmetric atoms are calculated for room temperature Argon and the quantum ground state of He-4. These correlations are studied through a distribution function. An approximate integral equation is derived for this pair-pair distribution function. The important aspects of the derivation include the use of the normalization integral (of a wave function) as a generating function. A function derivative is then applied to an approximation for the pair distribution function to obtain the integral equation. The pair-pair distribution is needed in the theory of second order light scattering (or Raman scattering). The Monte Carlo method is described and used to calculate the pair-pair correlation function for the quantum ground state of He-4. An integral equation for the three particle correlation function is derived. A solution for the three particle distribution function is found only in the low density limit.