Average Atom Model based on Quantum Hyper-Netted Chain Method

TL;DR

This paper introduces a method to accurately define the average ion charge in plasmas and liquid metals using the Quantum Hyper-Netted Chain approach, incorporating resonant states and deriving a general electron density formula without approximations.

Contribution

It presents a novel, approximation-free formula for electron density applicable within the QHNC framework, enhancing the modeling of plasmas and liquid metals.

Findings

Defined the exact average ion charge in electron-ion models.

Derived a general electron density formula based on density functional theory.

Validated the formula's applicability to the QHNC method.

Abstract

The study shows how to define "exactly" the average ion charge $Z_{\rm I}$ in the electron-ion model for plasmas and liquid metals: this definition comes out of the condition that a plasma consisting of electrons and nuclei can be described by the electron-ion model. Based on this definition of the average ion charge, the Quantum Hyper-Netted Chain (QHNC) method takes account of the resonant-state contribution to the bound electrons to form an ion. On the other hand, Blenski and coworkers have derived a formula to determine the electron density $n_0$ in a plasma as an electron-ion mixture by using the variational method with help of the local density approximation. Without use of any approximation, we derived the formula determining the electron density in an extended form on the basis of the DF theory. This formula is shown to be valid also for the QHNC method.