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`PMASS`

Fictitious mass for lattice degrees of freedom (in amu)
used in Parrinello-Rahman dynamics [79,80].

`PMASS=[real]`

Default

`PMASS=1000.`

The optimal setting of this parameter depends very much on the particular system at hand
and can be considered as a compromise between two opposing factors: too large value leads to
very slow variation of lattice degrees of freedom (and hence the sampling becomes inefficient)
while too small value could lead to too large geometric changes in a MD step and hence
could cause numerical problems. We strongly recommend to make careful tests with various settings
before performing the production run.

N.B. Requests for support are to be addressed to: vasp.materialphysik@univie.ac.at