[Wien] Bulk vs supercell Plasma frequency

[Muhammad Sajjad]

Dear Prof. Blaha

I did some calculation for Bulk Na (bcc, space gp #229_Im-3m) wiht k-mesh
30*30*30 and found the plasma frequency (in case.outputjoint) as
 Plasma frequencies:

       w_p_xx      w_p_zz    [eV]

       5.9446      5.9446

Now I constructed a supercell 1*1*6 (definitely symmetry reduced and now
sp.gp is 1_P1), used k-mesh 30*30*5 and  found
Plasma frequencies (much deviating from bulk values):

       w_p_xx      w_p_zz    [eV]

       5.76146      5.3446

Then used k-mesh 90*90*15 and found
Plasma frequencies (w_p_zz is deviating from bulk w_p_zz ):

       w_p_xx      w_p_zz    [eV]

       5.9485      5.8903

I have read the previous post (
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09782.html)
but it is not speaking about w_p_zz. So when I plot epsilon data for
w_p_xx then
it is matching with that of bulk but when I use w_p_zz  then it is
definitely  away from bulk. Should I consider w_p_zz  or use "number of
choice = 1 in case.inop" and plot epsilon only with w_p_xx ?


Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20151029/656c5abd/attachment.html>