Respected Prof. Stefano de Gironcoli and QE users,<br><br>
>Are the symmetry operations determined in the two systems the same ?<br><br>Yes.<br>
<br>>because there is a symmetry reason.<br>
>like a mirror plane or something ...<br><br> Na(H) and F have D3d , C3v site sym resp. <br><br>
>If your symmetry allows the born effective charge to be non zero they<br>
>will, much or little depending on the details of the system.<br><br>NaHF2 is mainly ionic than CuAlO2, so one may expect to have differences <br>in born-effective charges.<br><br>Thank you very much.<br><br>with regards,<br>
Sonu<br>IITD<br>