DEG THRESHOLD
DEGEN_THR = [real]
| Default: DEGEN_THR | = 2*10^{-3} |
Description: DEGEN_THR specifies whether two eigenvalues should be treated as degenerate during wavefunction clustering. DEGEN_THR is specified in units of eV.
This parameter is used to find clusters of wave functions within a given energy range. If it is set too high, non-degenerate eigenvalue pairs may be detected as degenerate pairs. Then, the inverse iteration will attempt to converge them. Ultimately, the program will get stuck and converge poorly. Conversely, too small a value might not detect all degenerate eigenvalues. The most severe problems are caused by very narrow semicore bands.
The POTCAR files contain a default ENMAX (and ENMIN). Therefore, it is, in principle, not necessary to specify ENCUT in the INCAR file. For calculations with more than one species, the maximum cutoff ENMAX (or ENMIN) value is used for the calculation (see PREC).
| Important: If you experience large drifts in the Born effective charges and adding more k-points does not help, try adjusting this parameter. |
Related tags and articles
ENMAX, ENMIN, ENINI, ENAUG, PREC, NGX, NGY, NGZ, NGXF, NGYF, NGZF, POTCAR