An auxilliary grid method for the calculation of electrostatic terms in density functional theory on a real-space grid

In this work we show the implementation of a linear scaling algorithm for the calculation of the Poisson integral. We use domain decomposition and non-uniform auxiliary grids (NGs) to calculate the electrostatic interaction. We demonstrate the approach within the PARSEC density functional theory code and perform calculations of long 1D carbon chains and other long molecules. Finally, we discuss possible applications to additional problems and geometries.