[Pw_forum] Site Occupancy

[Ahmet Cicek]

---------- Forwarded message ----------
From: Ahmet Cicek <islicam at gmail.com>
Date: Wed, Aug 20, 2008 at 11:21 AM
Subject: [Pw_forum] Site Occupancy
To: PWSCF Forum <pw_forum at pwscf.org>


Hi,

I am trying to obtain the band structure of Ammonium
Hexafluorosilicate-(NH_4)_2SiF_6-where the space group is Fm3m, location and
occupancies* of the base atoms are:

atom           position                        occupancy
------------------------------------------------------------------------
Si               (0,0,0)                             1
F                (0.2011,0,0)                     1
N                (0.25,0.25,0.25)               1
H                (0.168,0.168,0.269)          1/3

When the structure is contructed via symmetry operations, the number of the
H atoms are three times the actual value. Could you please help me in how to
use the knowledge of "occupancy" of the H atoms so that the band structure
calculation gives results corresponding to the physical structure?
Thank you.


*http://rruff.geo.arizona.edu/AMS/result.php?mineral=cryptohalite
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