Update to ACE‐molecule: Projector augmented wave method on lagrange‐sinc basis set

Abstract

The projector augmented wave (PAW) method was implemented in a quantum chemistry package that uses Lagrange‐sinc basis set, namely ACE‐Molecule. Its numerical accuracy has been assessed for the AE6 test set and compared with that of Hartwigsen‐Goedecker‐Hutter type pseudopotentials with nonlinear core correction. The PAW method shows a rapid convergence toward complete basis set limits of all electron calculations, whereas the pseudopotential method has a significant deviation even at small grid spacing. To alleviate spurious egg‐box effects, the so‐called supersampling method is adopted to the operation of projector functions. It improved accuracy of total energy calculations at substantially large grid spacing but did not show significant difference in atomization energies from the results without supersampling, which is due to error cancellation. © 2016 Wiley Periodicals, Inc.