The ABINIT Users Mailing List ( CLOSED )

[Bohdan Andriyevsky <bandri@tu.koszalin.pl>]

Dear 'Sevik',
I had right the same problem with another crystal: the calculated 
magnitudes of epsilon' (0 eV) obtained by 'optic' and 'anaddb' were very 
different. Unfortunately, I had no obtained an answer on similar 
question. The value of epsilon' (0 eV) obtained with 'anaddb' seem to be 
right. I think, we have to ask the Author of the program 'optic' for the 
help. I also have investigated that a similar problem of nonidentity 
arised when one calculates epsilon''(E) spectrum using 'optic' and 
'conducti' programs.

Regards,
Bohdan Andriyevsky
========================================================
DSc. Bohdan Andriyevskyy
Technical University of Koszalin
Sniadeckich Street 2, 75-453, Koszalin
Poland
e-mail: bandri@tu.koszalin.pl
phone: +48 94 3478690, +48 508070029
fax: +48 94 3433479


sevik@fen.bilkent.edu.tr napisał(a):

> I am trying to calculate frequency dependent dielectric function by using 
> optic code but optic code gives result chi(0 eV) = 1.42 and anaddb program 
> gives result \epsilon(O eV)=3.42. As I know that \epsilon(0 eV)= chi(O eV) + 
> 1 so the result of optic and anaddb program is not equal. Can anyone help me 
> about this problem my input file for abinit given below....
>
> #Compute GaAs crystal : ground-state with few bands,
> #then large number of bands, then ddk for different directions
> #
>
> ndtset 5
>
> #First dataset : SC run with 2 kpoints
> prtden1 1     getden1 0   getwfk1 0
> nband1  16     nstep1 100
> nbdbuf1 0 
>
> #Second dataset : NSC run with 32 kpoints, lots of bands
> iscf2 -2  getwfk2 1   getden2 1
> kptopt2 2
> # ddk response function
>   iscf3 -3
>   nqpt3  1
>    qpt3  0.0d0 0.0d0 0.0d0
>  rfdir3  1 0 0
> rfelfd3  2
> getwfk3  2
> kptopt3  2
> # ddk response function
> # ddk response function
>   iscf4 -3
>   nqpt4  1
>    qpt4  0.0d0 0.0d0 0.0d0
>  rfdir4  0 1 0
> rfelfd4  2
> getwfk4  2
> kptopt4  2
>
> # ddk response function
>   iscf5 -3
>   nqpt5  1
>    qpt5  0.0d0 0.0d0 0.0d0
>  rfdir5  0 0 1
> rfelfd5  2
> getwfk5  2
> kptopt5  2
>
> #Common data
> ngkpt 8 8 8
> kptopt 1     # Is this correct for preparation of optic ??
> optnlxccc 2
> acell   3*7.4009889150E+00
> amu 72.64 15.9994
> ecut 50.00
> iscf 3
> ixc 7
> natom  6
> nband 90
> nbdbuf 10
> nstep 200
> ntypat  2
> rprim   1.0 0.0 0.0
>         0.0 1.0 0.0
>         0.0 0.0 1.0
> xred    2.5000000000E-01  2.5000000000E-01  2.5000000000E-01
>        7.5000000000E-01  7.5000000000E-01  7.5000000000E-01
>        0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
>        0.0000000000E+00  5.0000000000E-01  5.0000000000E-01
>        5.0000000000E-01  0.0000000000E+00  5.0000000000E-01
>        5.0000000000E-01  5.0000000000E-01  0.0000000000E+00
>
> typat  2*1 4*2  tolwfr  1.e-22
> znucl 32 8
>
>
>