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QMAXFOCKAE

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Revision as of 05:27, 9 September 2026 by Huebsch (talk | contribs) (Explain the sentinel default of 0 (built-in values are used, it is not itself a wave vector) and the locked factor-of-two ratio; link shape restoration to the PAW formalism page; note that one value is read per species)
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QMAXFOCKAE = [real array]
Default: QMAXFOCKAE = 0 

Description: Sets the wave vector at which the local augmentation charges are fitted to restore the all-electron charge density on the plane-wave grid.


The fit is part of shape restoration, and NMAXFOCKAE gives how many wave vectors are used. One value is read per species, in the order of the species in the POSCAR file.

The default, 0, is not itself a wave vector but a sentinel meaning leave the built-in values alone. As long as it is 0, the fit uses

  • 6 Å-1 for NMAXFOCKAE = 1, a plane-wave energy of approximately 140 eV,
  • 5 and 10 Å-1 for NMAXFOCKAE = 2, approximately 95 eV and 380 eV.

A positive value replaces the first wave vector. The second is always twice the first and cannot be chosen independently, so with NMAXFOCKAE = 2 the setting

QMAXFOCKAE = 4

fits at 4 and 8 Å-1. With NMAXFOCKAE = 1 the single wave vector is taken from QMAXFOCKAE directly.

We do not recommend setting these values manually.

Related tags and articles

NMAXFOCKAE, LMAXFOCKAE, LMAXFOCK, LFOCKAEDFT, LFOCKSTD, Projector-augmented-wave formalism

Workflows that use this tag

References