[Pw_forum] Point Group from phonon calculation

[Izaak Williamson]

After running the phonon calculation for ZnO at gamma point, the frequencies were displayed as:

 **************************************************************************

     Mode symmetry, C_3v (3m)   point group:

     omega(  1 -  1) =        -26.3  [cm-1]   --> A_1  L_1        I+R
     omega(  2 -  3) =        101.8  [cm-1]   --> E    L_3        I+R
     omega(  4 -  5) =        110.3  [cm-1]   --> E    L_3        I+R
     omega(  6 -  6) =        253.3  [cm-1]   --> A_1  L_1        I+R
     omega(  7 -  7) =        379.8  [cm-1]   --> A_1  L_1        I+R
     omega(  8 -  9) =        398.5  [cm-1]   --> E    L_3        I+R
     omega( 10 - 11) =        426.6  [cm-1]   --> E    L_3        I+R
     omega( 12 - 12) =        540.6  [cm-1]   --> A_1  L_1        I+R

 **************************************************************************

I understand that A means the frequency is not degenerate and E means there is a degeneracy of 2. I just do not know what the L_1 and L_3 characters represent? Also, what does I+R mean?

Thanks,
Izaak Williamson
Physics Dept.
Boise State University



      
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