The ABINIT Users Mailing List ( CLOSED )

[c.gross@physik.uni-frankfurt.de]

Dear Lu Fu-Fa,
dear everybody,

Thanks for your reply - this was a step forward, as your input file at least 
works without producing warnings, if I replace the keyword 'ntype' (old ?) by 
'ntypat'.

However, I am still not really satisfied, as I do not understand whether this 
is the complete solution to my problem. The point is: In your input file, you 
have chosen to list 6 atoms, which is somewhere between the number of atoms 
in the asymmetric unit (3) and the total number of atoms in the unit cell 
(12). From these 6 positions, ABINIS figures out the spacegroup (#194) 
correctly (without the space group being explicitly specified by the keyword 
'spgroup'), but is the following calculation (of etot, for example) based on 
all 12 atoms, or just these 6 ? Why and how did you choose these 6 positions ?

I am not convinced that this the way the authors of ABINIS (hello, someone 
following this thread ? Please help...) actually had in mind. What, if I want 
to do a geometric optimisation of individual atoms afterwards ? Only 3 of 
these 6 positions are not related by symmetry, as enforced by the choice of 
the space group.

I would be thankful, if someone could sent me a working example with keyword 
'spgroup' of some known structure (does not have to be MgZn2, :-). Even 
better: Can someone please comment on the central question: If I specify the 
space group by keyword 'spgroup', do I have to specify more atomic position 
than just the asymmetric unit ?

Best regards,
Christoph

PS: Thanks to Lu Fu-Fa for the nice 'Navy link' !