The ABINIT Users Mailing List ( CLOSED )

[mmikami@rc.m-kagaku.co.jp]

Hello,

I am not familiar with the phase "cinnabar"(I am away from office now ...), 
still your input seems mind-boggling ...

From your input:
  (snip)
# acell: Nelmes&McMahon 1995 -> kindly give us complete information?
                                URL would be fine.
acell 7.7573257 7.7573257 17.757756
angdeg 90 90 120
  (snip)
spgroup 152
brvltt -1  ... (*1)
natom 2
ntypat 2
typat 1 2
xred 0.248888888 -0.042222222 0.291111111 (*2)
0.058222222 -0.387555555 0.445777777      (*2)

(*1) please check the help file:
http://www.abinit.org/Infos_v5.3/users/spacegrouphelpfile.html
(you will see, the definition,
 http://www.abinit.org/Infos_v5.3/users/spgrdefinition.html
 then, click "content", 
 http://www.abinit.org/Infos_v5.3/users/spgrdescription.html)
Kindly check #152 (P3_1 21). #152 allows "SPGAXOR 1" only.
(i.e. no "SPGXOR 2") So, I do not catch your comment 
about transformation "trigonal cell <-> hexagonal cell."

Then, check the Bilbao Crystallographic site to check "Wycoff positions":
http://www.cryst.ehu.es/cryst/get_wp.html
Input "152", and you will see the wycoff positions are :
 3a, 3b and 6c.(Note that #152 does not have any "1?" postions)
Thus, (*2) positions belong to "6c", so that your cell should contain 2 x 6 = 
12 atoms !(If your input might be right, I would be totally sure for this. 
;-))

Thus, I am afraid that you might have mistaken the information of the unit 
cell from the paper...

If the paper gives only the internal coordinations of inequivalent atoms, you 
could still make a nice ABINIT input file thanks to the keywords : spgroup & 
natrd :
http://www.abinit.org/Infos_v5.3/input_variables/vargeo.html#spgroup
http://www.abinit.org/Infos_v5.3/input_variables/vargeo.html#natrd

Please find inputs in test* in the tar.gz archives,and you can take one as a 
template for your input.

Good luck,
Masayoshi

P.S. The following site may be also useful:
http://cst-www.nrl.navy.mil/lattice/