[Wien] Optic calculation

[badis bennacer]

Dear Guan;
Well, I don't know which approximation you have used but the static 
dielectric constant is overestimated by the LDA which is attributed to the 
underestimation of the band gap by
this approximation ( see: F. Kootstra, P.L. de Boeij, J.G. Snijders, Phys. 
Rev. B 62 (2000) 707; F. Kalarasse and B. Bennecer , Journal of Physics and 
Chemistry of Solids, Volume 67, Issue 8 , August 2006, Pages 1850-1857). In 
order to correct for this LDA effect, one has to apply a constant energy 
shift to the conduction bands so as to match the calculated band gaps with 
the experimental data.

good luck

Badis Bennecer
Guelma Physics Laboratory (GPL)
University of Guelma
PO Box 401
Guelma 24000
Algeria



>From: "Guan Pengfei" <miracle.fei at gmail.com>
>Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>To: wien <wien at zeus.theochem.tuwien.ac.at>
>Subject: [Wien] Optic calculation
>Date: Thu, 31 Aug 2006 16:43:53 +0800
>
>Dear User£º
>          I calculation the optic properties of NaCl; the dielectric
>constant is 9.0; but the experimental value is ~ 6.0, Is't wrong with my
>calculation?
>          I got the value by this flow:
>                  run_lapw
>                  x kgen
>                  edit nacl.in2 "FERMI, TETRA 101"
>                   run_lapw -s lapw1 -e lcore
>                   x optic
>                   x joint
>                   x kram
>      the input files are :
>         nacl.inop
>286 1        number of k-points, first k-point
>-5.0 1.0      Emin, Emax for matrix elements
>2
>1             Re xx
>3             Re zz
>ON           ON/OFF   writes MME to unit 4
>         nacl.injoint
>    1   14                    : LOWER AND UPPER BANDINDEX
>   0.0000    0.00100   1.0000 : EMIN DE EMAX FOR ENERGYGRID IN ryd
>eV                            : output units  eV / ryd  / cm-1
>     4                        : SWITCH
>     2                        : NUMBER OF COLUMNS
>   0.1  0.1  0.3
>          nacl.inkram
>  0.00
>  0.0
>  0
>12.60   plasma frequencies  (from joint, opt 6)
>  0.20   Gammas for Drude terms
>
>Thanks for all advices!!!!!! I am crazy for the dielectric constant now:)
>                                                             Pengfei
>
>--
>--------------------------------------------------------------------------
>Guan Pengfei,  Ph. D
>Inst.f. Physics, Tsinghua U, Beijing, China
>Phone: +86-010-6218-2756        Mobile: +86-138-1060-9671
>Email: miracle.fei at gmail.com
>WWW: http://www.phys.tsinghua.edu.cn
>--------------------------------------------------------------------------


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