An enhanced RPA-LDA model for ion stopping power from cold matter to high-energy density plasmas: A unified, open-source framework

We present an enhanced random-phase-approximation–local-density-approximation (e-RPA-LDA) model for ion stopping power, valid from cold solids to high-energy-density plasmas. The electronic stopping is computed from the RPA dielectric response in the local-density approximation over an average-atom electron density obtained in a muffin-tin potential with the Flexible Atomic Code, augmented by four corrections to the earlier RPA-LDA model of Wang et al.: a strong-collision correction, a static local-field correction, an electron-binding correction, and the higher-order Barkas and Bloch terms. The resulting proton stopping powers agree with the NIST PSTAR and IAEA databases across the periodic table and for compounds, providing a physics-based alternative to semi-empirical codes like SRIM. It reproduces limited published plasma data, including charged-particle transport-workshop benchmarks, time-dependent density functional theory (DFT) calculations, and enhanced light-ion stopping in plasmas. We extend the model to a complete total stopping power for protons and alpha particles by adding nuclear and ionic stopping, yielding a continuous, self-consistent description of energy deposition from cold matter to hot dense plasmas. Our average-atom treatment includes all bound and free electrons self-consistently, reaching these conditions at lower computational cost than all-electron Kohn–Sham DFT stopping calculations, especially for high-Z targets and high temperatures. The model is well suited to inertial fusion and high-energy-density science. The computational framework is openly available on GitHub (https://github.com/dedx-erpa/dedx), with tabulated stopping powers and ranges for common materials in the data/ subdirectory.