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<div class="moz-cite-prefix">There is definitely no need to go to
such a high number of k-points. <br>
In the paper of Claudia, they were looking at metallic compounds,
for which we need to have a very dense k-mesh (for the intraband
transitions). <br>
In your case you expect a semiconductor and thus you will have
only interband transitions. Thus 6000 kpoints is already converged
to my point of view. <br>
I should say that the best way to insure the convergency in the
present case is to plot the epsilon2 as a function of the energy
for instance and to compare this quantity with different k-meshes.
In your case, try to do 300 kpoints first and then 500, 1000,
2000, 3000 kpoints ... You will certainly reach the convergency at
about 1000-2000 kpoints ...<br>
<br>
Regards<br>
<br>
Xavier<br>
P.S.: The values obtained for 90000 kpoints are curious but I
imagine that you had a prob<br>
<br>
<br>
Le 9/30/2013 4:59 PM, ali ghafari a écrit :<br>
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<div>Dear Prof. Blaha</div>
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<div style="color:rgb(0, 0,
0);font-size:16px;font-family:times new roman,
new york, times,
serif;background-color:transparent;font-style:normal;">I
have calculated the optical properties of TiSe2
by MBJ potential with 6000, 50000 and 90000
kpoints which generated after scf by x kgen as
discussed in the UG.<br>
As discussed in the paper of Prof. Claudia Draxl
(computer physics comm. 175, 1-14 (2006)) the
sum rule 1 and 2 show 'an effective number of
electrons contributing to the absoption process
as a function of energy'.<br>
but my calculations lead to :<br>
6000 kpoints: <br>
<pre>sum rule 1: Int(sigma)dw 19.14
sum rule 2: Int(eloss.w)dw 18.93
sum rule 3: Int(eloss/w)dw 1.51
</pre>
50000 kpoints<br>
<pre>sum rule 1: Int(sigma)dw 19.08
sum rule 2: Int(eloss.w)dw 18.94
sum rule 3: Int(eloss/w)dw 1.52</pre>
<pre>
90000 kpoints
sum rule 1: Int(sigma)dw 10.125
sum rule 2: Int(eloss.w)dw 10.035
sum rule 3: Int(eloss/w)dw 1.51
</pre>
the results show that in 90000 kpoints the value
of 'sum rule 2' significantly decreases . in the
UG it has mensioned that for the optic we need
dense kpoints but how many? how can I check it
for optic? <br>
Best Regards <br>
</div>
<div style="color:rgb(0, 0,
0);font-size:16px;font-family:times new roman,
new york, times,
serif;background-color:transparent;font-style:normal;">Ali</div>
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