[Wien] structeditor

[tran at theochem.tuwien.ac.at]

Hi,

FCC Cu has one atom in the primitive unit cell (the smallest possible
unit cell), but four in the conventional unit cell.
The primitive cell is rhombohedral. The conventional cell is cubic.

If you have xcrysden, then press F3 and F4 to switch between the primitive
and conventional cells.

F. Tran

On Fri, 28 Nov 2014, Lawal Mohammed wrote:

> Dear Profs. Peter and Robert,
> 
> Thank for your help.
> 
> My doubt is clear now, but when you said.....
> For FCC Cu, you have just ONE atom in the cell. I become comfused.
> I thought fcc Cu has FOUR atoms per unit cell i.e. corner atoms 8*1/8=1, and
> face centre atoms 6*1/2=3. 
> 
> And: Why would you like to do this ?
> We want to study the effect of vacuum on dot of a small unit cell, the study
> doesn't involve large vacuum size.
> 
>  Kind regards
> Lawal Mohammed
> 
> 
> On Thursday, November 27, 2014 3:09 PM, Robert Laskowski
> <rolask at ihpc.a-star.edu.sg> wrote:
> 
> 
> > > (2) How can I use vacuum in three directions using the structeditor?
> 
> assuming you loaded your struct to variable s, you may do the following:
> 
> s.a=s.a*factor;
> s.pos=s.pos/factor;
> showstruct(s)
> savestruct ....
> 
> where the factor a number bigger then 1, vacume layer should be
> (factor-1)*s.a(1:3) in all three directions
> 
> regards
> 
> Robert
> 
> 
> 
> 
> On 27 November 2014 AM 7:58:18 Peter Blaha wrote:
> > > (1) I am trying to make a replacement on interstitial sites of a given
> crystal system. But, it looks like the atomic ID in xcrysden doesn't
> represent the atomic index (ind)
> > > in the readme.txt of the structeditor. If I am right then, is there any
> package that can be used for that purpose?
> >
> > Think about this problem: For FCC Cu, you have just ONE atom in the cell,
> but of course,
> > xcrysden displays the full cell, i.e. 8+6 atoms. So there are "many"
> atoms, which would
> > have the same ID, thus the concept if "ID"s is difficult to visualize,
> because then you
> > would just see  "one single ball", which would not be helpful either.
> >
> > xcrysden allows to display the coordinates of the selected atom in
> "fractional coordinates"
> > and by this you can identify the atom in the structure.
> >
> > > (2) How can I use vacuum in three directions using the structeditor?
> >
> > I don't know how to do this and would need to study the help  myself.
> >
> > Instead:  x supercell can easily do it.
> >
> > And: Why would you like to do this ? It will be soon very expensive ....
> > Wien2k is NOT a "molecular code" and you should have good reasons to do
> this
> > in exceptional cases.
> >
> >
> 
> --
> ==================================================
> Dr. Robert Laskowski
> 
> Senior Scientist, Materials Science & Engineering Department
> Institute of High Performance Computing, A*STAR
> 1 Fusionopolis Way, #16-16, Connexis, Singapore 138632
> Tel(Off): +65. 64191493    Fax: +65. 64632536
> =================================================
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