Dear Gao: > The calculated phonon dos of 6-atom cell by matdyn.x is exactly two times as > large as that of 3-atom cell. > I guess that the phonon dos is not normalised to 3*nat, am I right? If "the calculated phonon dos of 6-atom cell is exactly two times as large as that of 3-atom cell.", the "phonon dos is normalised to 3*nat".