Diffraction corrections to the equilibrium properties of the classical electron gas. Pair correlation function

Abstract

We perform a systematic study of the diffraction corrections (h/≠0) in the high‐temperature range (k_BT≳1 Ry) for the pair correlation function of the one‐component classical electron gas with a neutralizing background, up to the third‐order in the plasma parameter Λ=e²/k_BTλ_D. This program is achieved through the effective interaction V_ee(r) = (e²/r)(1−e^−cr) with c ∼ (thermal De Broglie wavelength)⁻¹, allowing for a straightforward and tractable generalization of the one‐component classical plasma model. The nodal expansion of the potential of average force is performed order‐by‐order with finite Mayer‐Salpeter diagrams. The classical results of De Witt (second‐order) and Cohen–Murphy (third‐order) are recovered in the h/→0 limit. The resummation to all orders of the bubble diagrams gives access to the short‐range behavior of the pair correlation function, which is found similar with the Monte‐Carlo results.