Functions in Phonon
PHONON, version 4.24
Phonon ver. 4.24 contains all options of ver. 3.11.
Options of Phonon, ver. 4.24
perform the following functions:
- Space Group & Unit Cell - selection of the
crystallographic space group. All 230 space groups are given in
International Tables for Crystallography (1989) setting, and in Kovalev
- Particle Positions & Electric Charges - positions
& electrical charges of atoms in unit cell.
- Interaction Range / Coordination Shells or Supercell -
number of coordination shells, or shape and size of a supercell,
respectively, taken into account in construction of the dynamical
matrix. Generates POSCAR, or *.fdf input files for optimizing and
calculating the necessery Hellmann-Feynman forces by VASP, Siesta, or Wien2k. softwares, respectively.
Number of utilities facilitates to transfer data to and from the above
mentioned ab initio programs.
- Hellmann-Feynman Forces - converts the Hellmann-Feynman
(HF) forces to force constants. HF forces can be generated by a single,
or multiple atom displacements. Tranlational - Rotational Invariances
can be imposes. It is possibile further to refine the phonon modes by
fitting them to phonon frequencies comming from supercell calculations
of different shape, from linear response method, or from measurements.
- Import model - imports a model. There is about 60 models
with realistic force constants, or Hellmann-Feynman files.
- Fit Phonon Dispersion Relation to Desired Frequencies.
One may modify the calculated phonon branches supplying new
The new phonon frequency may come from linear responce method, direct
on supercells with different shapes, or precise measurements.
- Precise Calculation of Specific Modes.
The Hellmann-Feynmn file with ab initio forces can now be
supplemented with list of HF forces generated
with simultaneous displacement of many atoms of the supercell.
Multi-displacement pattern can provide higher accuracy for the
frequency of the soft mode. Works for 'exact' wavevectors.
- Phonons of Hexagonal Crystals are calculated in
supercell. Option 'Restore Symmetry' allows to rebuild hexagonal
- Dispersion curves - phonon dispersion curves along any
path in reciprocal space. Polarization vectors. Plot of phonon
intensities, partial phonon dispersion relations. Color plot indicates
a participation of an atom and its degree of freedom in a given phonon
branch. Different patterns of summing atom participation are supplied.
Calculates irreducible representations at the Brillouin zone center.
- Search Intensity in many Brillouin Zones. Intensities of
the phonon form factor in different Brillouin zones can be calculated
automatically. The same can be done for the coherent neutron scattering
factor. It allows to find the best Brillouin zone for measurements of
the coherent inelastic scattering of neutrons or X-rays.
- Automatic generation of displacement patterns. A
displacement pattern of any combination of phonon modes can be
generated in a format of VASP, Siesta and Wien2k programs. It allows
for precise frequency calculation of specific phonon modes.
- Animation of the phonon modes. Any pattern of phonon modes
can be exported to either *.pdb (Proteine Data Base) format, or *.xyz
format. These files can be directly animated by graphic software Molekel. written by S.Portmann,
or by MDL Chime. Plug-in
software to Internet Explorer. It proves to be realy exciting to watch
the vibrations of large part of crystallite. Useful for educational
- Density of states - total & partial phonon density
of states for all atoms and all polarization directions.
- Plot Thermodynamic Functions - internal energy, free
energy, entropy, heat capacity, and tensors of thermal displacements
(Debye-Waller factor) as a function of temperature.
- Coherent Dynamical Structure Factor - plot neutron
intensity in different Brillouin zones and different geometries.
Searches for extremal intensity.
- Neutron Scattering/Incoherent on Monocrystal &
Polycrystal - plot of doubly differential incoherent inelastic
neutron scattering cross section or S(k,w). One-, two-, ... five-phonon
scattering from the polycrystal are included The inelastic neutron
scattering on monocrystals can be averaged over any number of
orientations. It allows to find neutron spectra for textured samples.