[Wien] Different Plasma Frequency (PF) for bulk and supercell Na

[Muhammad Sajjad]

Dear Users

I have computed PF for bulk Na and its value is  *5.943 eV* with k-mesh
*18*18*18*.

Then I constructed a supercell 1*1*6 and run the calculation with different
k-meshes and obtained PF values. The details are

*K-mesh                        PF (x/z components in eV)*

*24*24*24                  5.7097   /   5.8192*


*36*36*24                  5.7614   /   5.8098  *


*50*50*10                  5.9358   /   5.6280 *

*50*50*30                  5.9365   /   5.8079*

My question is why PF is very sensitive to k-mesh selection? and which
value of PF is required for correct dielectric constant calculation? Do I
need *PF = 5.943 eV* for the supercell and then, definitely, need more test
calculation for right k-mesh selection?

-- 
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
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