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.
| Tip: If you experience large drifts in the Born effective charges and adding more k-points does not help, try adjusting this parameter. |
| Mind: This tag is only available from VASP.6.6.1 |