Ion energy-loss characteristics and friction in a free-electron gas at warm dense matter and nonideal dense plasma conditions

Abstract

The screening of a test charge by partially degenerate non-ideal free electrons at conditions related to warm dense matter and dense plasmas is investigated using linear response theory and the local field correction based on ab inito Quantum Monte-Carlo simulations data. The analysis of the obtained results is performed by comparing to the random phase approximation and the Singwi-Tosi-Land-Sjölander approximation. The applicability of the long-wavelength approximation for the description of screening is investigated. The impact of electronic exchangecorrelations effects on structural properties and the applicability of the screened potential from linear response theory for the simulation of the dynamics of ions are discussed.

Nonlinear interaction of external perturbations in warm dense matter

“…Prominent examples include the construction of effectively screened ionic potentials [83][84][85] and the electronic stopping power. [47] Specifically, going beyond LRT is a crucial step for understanding and exploring the effective ion-ion attraction in the media with strongly correlated electrons, [86,87] which remains to be an unsolved problem. [88,89] Additionally, the effect of electronic strong correlations on a projectile energy dissipation (stopping power) is one of the long-standing problems in WDM, [90,91] which can be addressed using the non-LRT.…”

“…In addition to f xc , accurate data for the warm dense UEG have been presented for a multitude of quantities including the static structure factor S(k), [25,[31][32][33] the momentum distribution function n(k) [34][35][36][37][38] the dynamic structure factor S(k, 𝜔), [39][40][41] and other dynamic properties like the conductivity. [42,43] Of particular importance for many practical applications [44][45][46][47] in WDM theory is the response of the UEG to an external perturbation. [2] Typically, such effects are described within linear response theory (LRT), which presupposes a simple, linear relation between response and perturbation and, thus, leads to a drastic simplification of the underlying theory.…”

Improving dynamic collision frequencies: impacts on dynamic structure factors and stopping powers in warm dense matter

“…DFT-AA models can go beyond the RPA by including static collisions and local field corrections [41][42][43] or dynamic collision frequencies ν(ω) in their calculations of dynamic response functions 10,44,45 using the Mermin modification to the RPA 46 . However, the accuracy of these corrections has not been rigorously assessed.…”

Ion modes in dense ionized plasmas through nonadiabatic molecular dynamics

“…The BO approximation thus neglects important details of the interaction and, of particular relevance to high energy density matter, the dynamics of electron-ion collisions are ignored [17]. Although justified for many equilibrium properties, like the equation of state [8,18], the adiabatic treatment prohibits direct energy transfer between electrons and ions and is therefore problematic for the modeling of transport properties and nonequilibrium matter [17,19,20].…”

“…Recent work has investigated the applicability of a Langevin thermostat to capture the effect of electron-ion interactions on the ion dynamics [8,18,21]. In this phenomenological approach, an additional stochastic Gaussian force is added to the equations of motion with a single collision frequency, or friction parameter, that must be determined a priori [20]. A number of classical (Rayleigh scattering [22]) and quantum (Born approximation [23]) models exist, but their applicability in the WDM state is unknown.…”