  An approach to compute the anharmonic peaks of the phonon dispersion curves
through the ab initio calculated Hellmann-Feynman forces from a series of
supercells with realistic atomic displacements of all atoms, which correspond
to a given temperature, is reported. Obtained phonon dispersion bands are able
to represent the positions and shapes of the anharmonic peaks. As example, the
approach to cubic PbTe and perovskite MgSiO3 crystals is applied.
