PHONON Software ver.6.10 / 6.11 / 6.12 / 6.13 / 6.14 / 6.15
PHONON Software ver.5.10 / 5.11 / 5.12

Temperature of solids is almost entirely determined by phonons. Phonons, in turn, are defined as a combination of atomic vibrations. Small atomic vibrational amplitudes lead to low temperature of the material. High amplitudes involve high temperature. Since the ambient temperature is always finite, all atoms of the whole world vibrate all the time. Thus, phonons are everywhere in solids.

Temperature dependence of any quantity of solid involves always phonons. To name only a few: phonons are responsible for thermal expansion, phonons contribute to appearance of phase transitions, and phase diagrams, phonons play a role in elastic and dielectric constants, transport processes, such as diffusion and chemical reactions, catalysis, superconductivity, ferroelectricity, shape memory alloys, etc. Moreover, phonon properties can be substantially modified when the crystal is decorated by defects, like additional atoms, precipitates, interfaces, grain boundaries, or surfaces.

Phonons are specified in the lattice dynamics theory. This theory, due to fast and powerful computers, allow to calculate phonon characteristics using first-principle or ab initio methods. At present phonons in many systems, can be computed without any adjustable parameters. Hence, the calculated lattice dynamics becomes a complementary tool to the measurements.

The Phonon Software allows to calculate the phonon characteristics. As an input this software requires to know (i) a crystal structure, and (ii) a file of Hellmann-Feynman forces. External ab initio program like VASP, Wien2k, MedeA of Materials Design, or Siesta can be used in this respect. The Phonon Software plots the dispersion curves, phonon density of states, thermodynamical functions, neutron and x-rays spectroscopic spectra, and many others quantities. With additional calculations of effective charges and dielectric constant the infrared and Raman spectra can be determined for variety of experimental geometries.