Probing ion-ion and electron-ion correlations in liquid metals within the quantum hypernetted chain approximation

Abstract

We use the quantum hypernetted chain approximation to calculate the ion-ion and electron-ion correlations for liquid metallic Li, Be, Na, Mg, Al, K, Ca, and Ga. We discuss trends in electron-ion structure factors and radial distribution functions, and also calculate the free-atom and metallic-atom form factors, focusing on how bonding effects affect the interpretation of x-ray scattering experiments, especially measurements of the ionion structure factor in the liquid metallic phase.

Integral equation model for warm and hot dense mixtures

“…This procedure has be extensively described for the homo-nuclear case [12,22]; here we give only the salient details. We assume that there exists an effective N -component system of classical particles, interacting through short ranged pair potentials V IJ (r) such that the ion-ion pair correlation functions h IJ are identical to those of a corresponding 4 (N +1)-component system of classical particles and quantal electrons.…”

Partial ionization in dense plasmas: Comparisons among average-atom density functional models

“…A more general approach would contain both electronand ion-equations, solved self-consistently, to yield electron and ion density distributions. This approach has been implemented previously by several authors within OFDFT [39][40][41] and in Kohn-Sham formulations [42]. The ion subsystem obeys classical statistical mechanics.…”

“…In the current literature involving heated, solid-density or compressed targets [83][84][85][86][87], the working assumption that n e = Z f n i has been used to infer Chihara's Z f from the relative strengths of the first two XRTS terms in (42), or from the electron density that the measured position of a plasmon feature yields. Some of these experiments have shown certain orbital-based MIS values to be in reasonable agreement with data for plasmas at varying temperatures, while Saha-type MIS values underestimate the inferred degree of ionization at low temperatures.…”

“…Because of the importance of this interaction at very high densities, as we have seen, and the ready availability of a fit for it (recall (15)), improved Z fits should be produced for a TFxc model; together with finite-temperature gradient corrections, a more accurate orbital-free model may result. Combining such a model with ionic structure [39,41,42] may yield a more accurate, all-electron model that includes self-consistent ionic correlations. The notion of an average atom with a definite MIS provides a simple one-parameter, finitetemperature pseudo-potential for describing ions in plasmas; determining, for example, ion-ion dynamic structure factors using more accurate ionic models could involve, e.g., atomic shells of specified radii and well depths [8].…”

“…These approaches include many correlated ions spherically averaged around one nucleus [39][40][41][42]. We do not consider these methods which are relatively less developed, especially in dealing with the MIS, which is our main focus.…”