Estimating the ion correlation parameter from EXAFS experiments on dense plasmas

Abstract

The analysis of extended X-ray absorption fine structure (EXAFS) data by Djaoui et al. (1989) led to normalised estimates of the value of Lambda , the ion correlation parameter, partly due to the uncertainty in the ionization state of the Al plasma. The author adopts simplified version of the interatomic force model of Laughlin (1986) to include the effect of electron screening and shows how to estimate the temperature dependence of the Debye-Waller factor for a dense plasma system. This allows the experimental values of the Debye-Waller factor to be used to give limits on both the temperature and, via the Thomas-Fermi ionisation formula of More (1985) on Lambda . A subsequent assumption allows estimates of the actual correlation parameter, which are physically reasonable for the experiment in question. The author discusses how it will be necessary to develop a model using radial distribution functions to examine properly the question of temperature estimation from EXAFS experiments in the dense plasma regime.