[Wien] 'stop - follow, nstep > maxfoll' in aim

[Kevin Jorissen]

Hello WIEN-users,

I try to calculate the Bader-charge of an atom using the aim-program and a
pretty default input-file case.inaim :

SURF
1                          atom in center of surface
20 0.0 3.1415626535     theta, 20 points, from zero to pi/2
40 0.0 6.2831853072       phi, from pi/4 to  3 pi/4  (depends on symmetry!!)
0.07 0.8 4                 step along gradient line, rmin (when reached it
assumes the gradient line ends at the atom), every 4th step it checks wether
gr.path is behing/in front an already found surface
1.6 0.1                    initial R for search, step (a.u)
2 2 2                      nshell
IRHO                       "INTEGRATE" rho
WEIT                       WEIT (surface weights are available in
case.surf), NOWEIT if surface put int by hand
30                         30 radial points outside min(RMIN,RMT)
END


For some materials this seems to work, i.e., it produces charges that appear
reasonable and are only very slightly sensitive to some of the input options
that I varied.
In another case (a simple calculation for MnO2), the program stops rather
soon and writes to the screen :
follow

Judging from case.outputaim, it has obviously not ended its task.  The last
lines read :
[...]
distance to atom  -1    3.7027
:PC   0.313181  0.686819
 0.935392 -0.1506E-01 -0.2760E-01 -0.2066E+00  -3 -0.2493E+00  0.1862E+00
:POSOUT   0.260640E+01  0.571596E+01  0.508372E+01
:STEP    2 r=  2.41944033 iat=   0 ipos=   0 time(sec)=   1.95000 nstep=  68
:POSINIT   0.308557E+01  0.614706E+01  0.324576E+01
 We are inside a pseudo-atomo
:POSOUT   0.266922E+01  0.573260E+01  0.504469E+01
:STEP    3 r=  2.31944033 iat=   0 ipos=   0 time(sec)=   0.62000 nstep=  26
:POSINIT   0.313195E+01  0.606144E+01  0.322298E+01
 :NSTEP gt maxfoll          501         500

Of course, I could try to raise maxfoll.  But as the imposed limit of 500
worked fine for other cases (using the same case.inaim), I suspect I'm
making a mistake here, probably because I don't fully understand all the
input options.

Can anyone offer me some good advice ?

Thanks,

Kevin
EMAT
University of Antwerp
Belgium
kevin.jorissen at ua.ac.be