<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><div><font face="times new roman, new york, times, serif">Hello,</font></div><div><font face="times new roman, new york, times, serif"><br></font></div><div><font face="times new roman, new york, times, serif">I have performed a phonon calculation using ph.x. During the scf calculation (prior to using ph.x), the ATOMIC_POSITIONS is in Bohr units. I am also using ibrav = 0 and an orthorhombic crystal system. After ph.x, I have used dynmat.x to apply asymmetric sum rule and get the new phonon eigenvalues and eigenvectors. The output of dynmat.x has the following format: </font></div><div><font face="times new roman, new york, times, serif"><br></font></div><div><font face="times new roman, new york, times, serif"><br></font></div><div><font face="times new roman, new york, times, serif"> omega(12)
= 1.305968 [THz] = 43.562397 [cm-1]</font></div><div><font face="times new roman, new york, times, serif"> ( -0.052340 0.000000 -0.021008 0.000000 0.002346 0.000000 )</font></div><div><font face="times new roman, new york, times, serif"> ( -0.003841 0.000000 -0.009204 0.000000 0.053835 0.000000 )</font></div><div><font face="times new roman, new york, times, serif"> ( 0.014655 0.000000 -0.015822 0.000000 0.085998 0.000000 )</font></div><div><font face="times new roman, new york, times, serif"> ( -0.013791 0.000000 -0.035434 0.000000 0.066956 0.000000 )</font></div><div><font face="times new roman, new york, times, serif"><br></font></div><div><font face="times new roman,
new york, times, serif">While the units of omega is evident, the unit of eigenvectors is not clear. I wonder what is the unit of eigenvectors ?</font></div><div><font face="times new roman, new york, times, serif"><br></font></div><div><font face="times new roman, new york, times, serif">The atomic position have the following units:</font></div><div><font face="times new roman, new york, times, serif">ATOMIC_POSITIONS { alat | bohr | crystal | angstrom }</font></div><div><font face="times new roman, new york, times, serif"><br></font></div><div><font face="times new roman, new york, times, serif">Do the phonon eigenvectors have the same units as atomic positions or they have one particular unit always ? If it is one particular unit then what it is ? I noticed that the dynamical matrix is written in cartesian axes (I assume it means in the units of alat). </font></div><div><font face="times new roman, new york, times,
serif"><br></font></div><div><font face="times new roman, new york, times, serif">Thanks,</font></div><div><font face="times new roman, new york, times, serif"><br></font></div><div><font face="times new roman, new york, times, serif">David</font></div></div></div></body></html>