posted on 2024-04-10, 14:37authored byYu-Chieh Chi, Chen Huang
A major
obstacle hindering the application of orbital-free density
functional theory (OF-DFT) to all metals is the lack of accurate local
pseudopotentials (LPSs), especially for transition metals. In this
work, we developed high-quality LPSs for all simple and transition
metals by fitting the atomic eigenvalues and orbital norms beyond
the cutoff radii. Due to the lack of nonlocality in LPSs, it is very
challenging to simultaneously fit the semicore and outermost valence
orbitals of transition metals. We overcame this issue by excluding
the semicore orbitals from the LPS optimizations. This allows us to
achieve excellent fittings of the outermost valence orbitals, which
are responsible for chemical bonding. The norm-conserving condition
is then satisfied, leading to high-quality LPSs. To construct LPSs
for magnetic systems, we introduce an additional metric: the atomic
spin-polarization energy. By including this metric in the fitting,
the LPSs reasonably reproduced many properties of magnetic metals
and alloys. The high-quality LPSs developed in this work bring us
one step closer to large-scale, reliable OF-DFT simulations of all
metals and their alloys.