The ABINIT Users Mailing List ( CLOSED )

[Masayoshi Mikami <mmikami@rc.m-kagaku.co.jp>]

Hello there,

About nsym/symrel ... etc.
You can use the default "nsym 0" for ordinary purpose.
    http://www.abinit.org/Infos_v5.3/input_variables/varbas.html#nsym
As described in the helpfile (see the above link), it will be  
automatically set
by the code. You do not need set symrel, either:
    http://www.abinit.org/Infos_v5.3/input_variables/varbas.html#symrel

Instead, you would like to set "spgroup", if you know your system.
Otherwise, prepare all the positions of atoms in your unit cell, and
the information on the symmetry will be automatically obtained by the  
code.
(please check typical input files using such keywords by "grep -ir",
  as suggested in the Netiquette :
    http://www.abinit.org/community/?text=netiquette)

In passing,
to know/check about the symmetry, the following sites would be helpful.

 a) http://www.cryst.ehu.es/ (e.g., "GENPOS")

 b) http://cst-www.nrl.navy.mil/lattice/index.html
   From there, you can go inside, e.g.
   http://cst-www.nrl.navy.mil/lattice/spcgrp/index.html
->http://cst-www.nrl.navy.mil/lattice/spcgrp/cubic.html
   You can find typical crystal structures with relevant information.

Good luck,
Masayoshi

P.S. You would not like to put your name in the mails, would you ?

On 2007/04/25, at 13:54, taoj0003@ntu.edu.sg wrote:

> nsym gives number of space group symmetries to be applied in this  
> problem. but how can i know what's the number related to my system?  
> for example, what is the number for BCC,FCC,and others? where can i  
> find the defination of this? thanks.
> also symrel can be used to give the symmetry, what's the difference  
> between these two? how to use them. ?