[Pw_forum] titania crystal stucture

[José C. Conesa]

On 9 May 2006 at 8:20, Luke Thulin wrote:

> Hello,
> 
> I'd like to model the band structure of anatase titania, but I'm having 
> more difficulty than I expected just finding the coordinates for the 
> atoms in the unit cell.  So far I've only been able to find out that it 
> has some type of tetragonal or body centered tetragonal structure with a 
> = 3.785A and c=9.514A.  Can anyone help me fill in the rest of what I 
> need to enter the structure into QE so I can get a good visual of it in 
> XCrysDen?  Or for future reference, does anyone know of any resources, 
> online or otherwise, of the crystal structures of some common compounds 
> such as this?
> 
There are a number of crystallography databases where you can search structures 
online. A great one is ICSD, but only a small fraction of the structures is available to 
nonsuscribed institutions; even in that case, a good set of the most fundamental ones 
can be retrieved freely there through the access at
http://icsdweb.fiz-karlsruhe.de/index.php 
Other interesting structure servers are:

http://rruff.geo.arizona.edu/AMS/amcsd.php
http://cst-www.nrl.navy.mil/lattice/

but surely there are more. Perhaps if yopu look with google for "crystal structure 
database" you would find some of them. Of course, knowing how to handle a crystal 
description (with space group, taking into account settings, etc.) is quite impoertant to 
know what to do with the structure descriptions. For such structure handling, and also 
visualization and symmetry operations, a good program is PowderCell for Windows 
(now at version 2.4; free to download), see:
http://www.ccp14.ac.uk/ccp/web-mirrors/powdcell/a_v/v_1/powder/e_cell.html
Good luck,

Jose C. Conesa
Instituto de Catalisis y Petroleoquimica, CSIC
Campus de Cantoblanco
28049 Madrid  -  Spain
Phone Nr. 34-91-5854766
Fax Nr. 34-91-5854760