Projector augmented-wave method

TLDR

The method extends the LAPW approach, enabling affordable treatment of first‑row and transition‑metal elements while providing access to the full wave function. The study proposes an electronic‑structure approach that naturally generalizes both the pseudopotential and LAPW methods. It generalizes partial‑wave expansions using projector functions, allowing high‑quality Car–Parrinello molecular dynamics and recoverable pseudopotential limits. The approach permits high‑quality first‑principles molecular‑dynamics simulations via the Car–Parrinello Lagrangian.

Abstract

An approach for electronic structure calculations is described that generalizes both the pseudopotential method and the linear augmented-plane-wave (LAPW) method in a natural way. The method allows high-quality first-principles molecular-dynamics calculations to be performed using the original fictitious Lagrangian approach of Car and Parrinello. Like the LAPW method it can be used to treat first-row and transition-metal elements with affordable effort and provides access to the full wave function. The augmentation procedure is generalized in that partial-wave expansions are not determined by the value and the derivative of the envelope function at some muffin-tin radius, but rather by the overlap with localized projector functions. The pseudopotential approach based on generalized separable pseudopotentials can be regained by a simple approximation.