The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

On 11 Jun 2006, at 18:10, Nuno A. G. Bandeira wrote:

> Dear abiniters,
>
> Can anyone tell me how I can manually specify a screw axis in my  
> model ?
> Symrel does not accept real numbers only integers so I wonder if  
> anyone has ever tried this.

You need to defined tnons . Only integers are needed for symrel.
Examples of tnons and symrel for enantiomorph crystals, where screw  
axes are common,
are given in the OUTPUT file of test v3 # 21 (see the Reference fiiles).
Warning : to specify values of tnons in input files, use fractionary  
notation instead of a finite
number of digits (usually too few for ABINIT). So, use 1/3 instead of  
0.333333.

Xavier