Functions in Phonon
PHONON, version 4.28 / 4.30
Phonon ver. 4.28 contains all options of Phonon, ver. 4.24.
Phonon ver. 4.30 contains all options of Phonon, ver. 4.28, and it may
work for crystals containing any number of atoms. Limit is imposed by the computer memory now.
The performance of Phonon, ver. 4.28, with respect to ver. 4.24,
is greatly improved.
In particular, for
the "Hellmann-Feynman/DO Report" option the computing CPU time is
shortened by a factor of 10 - 100, depending on the supercell size and
There are now two versions to calculate the force constants
from Hellmann-Feynman forces. First, permits to find the force constants
from single (+/-) displacements of non-equivalent atoms of the crystal
unit cell. Second, allows to supplement the Hellmann-Feynman file by
forces generated by simultaneous displacement of many atoms of supercell,
for example those which form a specially interesting phonon mode.
There is about 140 predefined models with realistic force constants,
or Hellmann-Feynman forces.