[Pw_forum] A query about the PRIMCOORD parameter of the Xcrysden.

[zhaohscas]

Hi all,

I've seen the Xcrysden documentions at the url:

http://www.xcrysden.org/doc/XSF.html

On the above url, there're the following descriptions:

---------------------------------------------
Here is an example of ZnS crystal structure: 

 CRYSTAL                                        see (1)
 PRIMVEC
    0.0000000    2.7100000    2.7100000         see (2)
    2.7100000    0.0000000    2.7100000
    2.7100000    2.7100000    0.0000000
 CONVVEC
    5.4200000    0.0000000    0.0000000         see (3)
    0.0000000    5.4200000    0.0000000
    0.0000000    0.0000000    5.4200000
 PRIMCOORD
 2 1                                            see (4)
 16      0.0000000     0.0000000     0.0000000  see (5)
 30      1.3550000    -1.3550000    -1.3550000
---------------------------------------------

In the above descriptions,  if we take the sulfur atom position as the origin, than the Zinc atom should have the coordinates  (-1.3550000    -1.3550000    -1.3550000).  I don't konw why it should be  (1.3550000    -1.3550000    -1.3550000) in the Xcrysden's documents.

Who can give me some hints on this?

Sincerely yours,
Hongsheng.
------------------				 
Hongsheng Zhao <zhaohscas at yahoo.com.cn> 
Xinjiang Technical Institute of Physics and Chemistry
Chinese Academy of Sciences 
GnuPG DSA: 0xD108493

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