I used optics to work out the EPS and found a strange phenomena:
0 NaN NaN
………………………………
0.4500000000000000 15.8730650828125700 82.4986122823371300
0.4548875000000000 15.6280745773936700 81.7180399923139000
0.4597750000000000 15.3872837289285700 81.0039784860626400
………………………………
Why the imaginary parts of the dielectric function(the last coulmb) are so large?And I see that of larger energy range seems OK.
I appreciate for any help.
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about dielectric function
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linglin
about dielectric function
Last edited by linglin on Thu Jun 18, 2009 10:08 am, edited 1 time in total.
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irene
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about dielectric function
What kind of system are you dealing with? Is it metallic?
Last edited by irene on Fri Jun 26, 2009 1:00 pm, edited 1 time in total.
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linglin
about dielectric function
No, it's a insulator.(Badgap is about 4eV) I calculate again using VASP5.2. There's no NaN, but also very large value, and reach 0 abruptly when energy=0.
Last edited by linglin on Sat Jun 27, 2009 6:03 am, edited 1 time in total.
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linglin
about dielectric function
Can VASP5.2 deal with f electrons? I calculate the optical properties of a system containing 7 f electrons.
Last edited by linglin on Mon Jul 06, 2009 1:36 am, edited 1 time in total.
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alex
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about dielectric function
yes
Last edited by alex on Mon Jul 06, 2009 8:04 am, edited 1 time in total.
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linglin
about dielectric function
Thank you. So the weird phenomenon may attribute to the divergency problem? I set NBANDS=190 for 94 valence electrons for considering ISPIN=2. It needs large memory……
Last edited by linglin on Mon Jul 06, 2009 11:20 am, edited 1 time in total.
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irene
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about dielectric function
Do you get a LDA gap of 4 eV?
Are you using the tetrahedron method?
Are you using the tetrahedron method?
Last edited by irene on Tue Jul 07, 2009 9:14 am, edited 1 time in total.
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linglin
about dielectric function
I use GGA-PBE.
Yes, ISMEAR=-5
Yes, ISMEAR=-5
Last edited by linglin on Wed Jul 08, 2009 2:18 am, edited 1 time in total.