A simple method for determining the ionic structure of warm dense matter

A model for dense homo-nuclear plasmas that couples an average atom model for the calculation of the electronic structure to the quantum Ornstein-Zernike equations describing the ionic structure is summarized and described pedagogically. The model is applied to the calculation of ion-ion pair distribution functions g(II)(r) for tungsten in the warm and hot dense matter regimes. These results are compared to orbital-free molecular dynamics simulations and excellent agreement is found. Calculations of g(II)(r) with a simple version of the model (which we call the ion-sphere model) are in remarkable agreement with those of the full model. This ion-sphere model provides a simple and efficient method of calculating accurate g(II)(r) for warm and hot dense matter for many applications involving low- to high-Z elements with a modest investment of effort. (C) 2013 Elsevier B.V. All rights reserved.