Cubic spline solver for generalized density functional treatments of atoms and generation of atomic datasets for use with exchange-correlation functionals including meta-GGA

Within generalized density functional theory, recent developments of functionals which depend upon the kinetic energy density, such as the r2SCAN form, show significant improvement in the computational representation of real material properties. In order to implement these forms within plane-wave codes, it is necessary to use pseudopotentials, ideally constructed with the same exchange-correlation functional as has been implemented for the projector augmented-wave (PAW) formalism in the ATOMPAW code. This was accomplished with the help of an efficient solver for the self-consistent radial bound states of each atom, based on cubic spline interpolation. Details of the formalism are presented, and preliminary results for several simple materials are encouraging.