Improved calculations of electron–ion bremsstrahlung Gaunt factors for astrophysical applications

Electron–ion bremsstrahlung (free–free) emission and absorption occur in many astrophysical plasmas for a wide range of physical conditions. This classical problem has been studied multiple times, and many analytical and numerical approximations exist. However, accurate calculations of the transition from the non-relativistic to the relativistic regime remain sparse. Here we provide a comprehensive study of the free–free Gaunt factors for ions...