The ABINIT Users Mailing List ( CLOSED )

[Stephane BECU <stephane.becu@st.com>]

Dear Henry,

You can calculate the frequency-dependent dielectric tensor by DPFT. To do
soyou have to build databases for second and third energy derivatives with
respect to electric fields and atomic displacements. Three actions must be
done to perform the complete calculation:
1/ run an input file (using "abinis.exe" executable) made of 5 datasets:
 - Dataset 1: self-consistent calculation in the IBZ
 - Dataset 2: non self-consistent calculation to get the wf over the full
BZ
 - Dataset 3: ddk calculation
 - Dataset 4: derivatives with respect to electric fiuelds and atomic
displacements
 - Dataset 5: non-linear response calculation to get the static dielectric
constant and non-linear optical susceptibility

This step can be very long depending on your natom, nband, ecut, ngpkt...
Choice.
 
2/ once you have generated your output file and the correspondoing ddb files
(at the end of the first action) you'll have to merge the ddb files of
dataset 4 and 5 using the "mrgddb.exe" program: by default these are called
inputfilename_DS4_DDB and inputfilename_DS5_DDB. It will output a
"inputfilename.ddb.out" file. This step will last only few seconds.

3/ once the .ddb.out file has been generated you'll have to run the
"anaddb.exe" executable program. It will last only few seconds and will
generate a final .out file containing the frequency-dependent dielectric
tensor.

Don't hesitate to have a look to the so-called "Tutorial on static
non-linear properties" in the abinit package. It gives all the informations
you'll need to make your calculations.

Sincerely,

Stéphane Bécu
PhD student
ST Microelectronics
38926 Crolles, Cedex
France



-----Original Message-----
From: lfe11@yahoo.com.tw [mailto:lfe11@yahoo.com.tw] 
Sent: Monday, March 13, 2006 10:23 AM
To: forum@abinit.org
Subject: [abinit-forum] about anddb code


Dear all:

The anaddb code can calculate the frequency-dependent dielectric tensor. But
I don't know how to get the ddb file that can do the job. Are there some
input files that can do the calculation in Test_V1~4? Thank for your help.
                                                   Henry Chen