[Pw_forum] further: born charges in rhombohedral unit cell.

[sonu kumar]

Respected Prof. and QE users,

>so, i guess, Na(H) should have diagonal Z*

Yes.

>while F could have off
>diagonal one and could be non-symmetric ...

No, it also has only diagonal elements, which are* (along with H and Na)
(prb 73, 155114, ͑2006,      section VII, part-C*)

 direction                      H           F          Na*

xx/yy*                         ~0.34     ~ -.7     ~1.06
zz                               ~2          ~ -1.5   ~ 1


Thank you.

with regards,
Sonu
IITD
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