The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

Dear Artem,

Artem Oganov wrote:
> Dear ABINITioners,
>
> I have done a number of calculations using AIM. My idea was to perform Bader
> analysis for the same material (SiO2 stishovite) at a number of pressures.
> The results were, however, strange: the number of all types of critical
> points varied with pressure in situations when it should not vary (for a
> clear octahedral coordination at high pressure I get 4 bond critical points
> instead of 6!). Perhaps someone has ideas about that?
> I have studied 4 different materials, and 3 out of 4 have this problem. Is
> it a bug in the code? Or perhaps there is a problem in my input file:


The AIM code is quite robust as concerns the integration on the
density (to get the Bader atomic charge). For the critical points, the 
situation
is much more delicate, and I found recently that the control that the user had
on input variables could be improved (some parameters had "adhoc" values,
that were not sufficiently transferable). In v4.0.3, you will find
an improved help file, explaining more of the method,
as well as access to new input variables. This should allow you to
understand how to tune the search for critical points. There are also
additional automatic tests.

Good continuation,
Xavier