[Pw_forum] in ralax out file :what the tau( 1) stand for ?

[Eyvaz Isaev]

--- xu yuehua <njuxuyuehua at gmail.com> wrote:

>  hi all
> i want to check the the position of atoms
> generateing from my input ,but i
> do not know the "tau "stands for
> 
> outfile:
> 
>  Cartesian axes
> 
>      site n.     atom                  positions
> (a_0 units)
> 
>          tau(  1) = (   0.0955000  -0.0222921  
> 0.0877964  )
>            tau(  2) = (   0.1203713   0.0259950  
> 0.1476673  )
>          tau(  3) = (  -0.0913367  -0.0311881  
> 0.0864053  )
>          tau(  4) = (  -0.0933862  -0.0952227  
> 0.0371086  )
>          tau(  5) = (  -0.1146783   0.0578960  
> 0.1453950  )
>           tau(  6) = (  -0.0622673   0.0735890  
> 0.0858806  )
>           tau(  7) = (   0.0005149  -0.0944603  
> 0.1013409  )
>          tau(  8) = (   0.0589802  -0.1140741  
> 0.1536128  )
> wish your assist

Dear, Xu, 

The answer is given right after "Cartesian axes":
atomic position of atom j of type i and atomic
position is in cartesian coordinates which are scaled
by lattice parameter a_0. 
If you have troubles reading such a kind information,
you  should first read any solid state physics
textbook by, as example, Kittel, Aschkroft-Mermin,
Ziman, Harrison etc.

Bests,
Eyvaz.

> -- 
> Xu Yuehua
> physics Department of Nanjing university
> China
> 


-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, and 
Condensed Matter Theory Group, Uppsala University, Sweden Eyvaz.Isaev at fysik.uu.se, eyvaz_isaev at yahoo.com


       
____________________________________________________________________________________Be a better Globetrotter. Get better travel answers from someone who knows. Yahoo! Answers - Check it out.
http://answers.yahoo.com/dir/?link=list&sid=396545469