I'd recommend to increase the integration parameter a bit.

We've noticed such convergence problems occasionally with molecular
geometries that are slightly displaced from the minimum, using similar or
tighter SCF convergence criteria, even with INTEGRATION setting of 8 or
higher.

In your case, perhaps you can get past that freq. displacement step by
increasing the second SCF convergence parameter to 1e-5, calculate step
29, and continue with the original settings?

Jochen

On Sat, 18 Feb 2006, Alvin Chang wrote:

> Hi, all.

    Today I met a problem about failure of SCF convergence in freq
calculation after the geom opt calculation.

The end of logfile says
" <Feb18-2006> <23:36:46> More iterations needed. NOT CONVERGED
 <Feb18-2006> <23:36:54> 300 ErrMat 0.00000365 MaxEl -0.00000128
 <Feb18-2006> <23:36:55> >>>> TOTEN
 <Feb18-2006> <23:37:14> >>>> POPAN
 <Feb18-2006> <23:37:14> >>>> DEBYE
 <Feb18-2006> <23:37:14> >>>> AMETS
 <Feb18-2006> <23:37:14> SCF NOT COMPLETELY CONVERGED
 <Feb18-2006> <23:37:14> STOP GEOMETRY ITERATIONS
 <Feb18-2006> <23:37:14> NORMAL TERMINATION
 <Feb18-2006> <23:37:14> END
"
   I customized the same parameter in opt and the following freq calculation
in SCF block, shown as
"scf
 iterations 300
 converge 1e-7 1e-6
 Mixing 0.2
end
"
  Other option was
 converge grad=1e-4 in opt;
 Integration 5.5 in opt , 6.5 in freq;

   In opt, SCF convergence was OK, while in freq, it failed in " Frequency
Displacement 29".

   Cartesian coordinates was employed in both calculations of the "
lanthanide + alkane " system.

   So, what's the matter of my calculations ?

   Thanks in advance.

   Best regrads

--
so let us be up and doing
with a heart for any fate
still pursuing and still achieving
learn to labor and to wait
---------------------------------------------------
 Dr. Jochen Autschbach      
 Assistant Professor
 Department of Chemistry
 University at Buffalo
 State University of New York
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 EMail : jochena_at_buffalo.edu
 Phone : (+01)-716-645-6800 ext. 2086
 FAX   : (+01)-716-645-6963
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