Subject: G98: opt=stable and freq

From: DE BRUIN theodorus <[email-masked]>
Date: Wed, 21 Aug 2002 10:58:47 +0200

Dear all,

I am studying a system in which I am cracking a bond homolytically in a
stepwise manner with B3LYP. I found that upon increase of the bond length
the wavefunction becomes unstable, i.e. it converges to a singlet state. I
tested the wf with G98 with stable=opt and this calculation confirmed the
instabilty.

However, I wish now to do a freq analysis on the new (stable) wavefunction.
The keywords freq and stable=opt do not go together:
 Illegal IType generated by parse.
 Error termination via Lnk1e in /home2/debruint/bin//g98/l1.exe.
On the other hand, if I perform a --link1-- job, in which I first do the
stable=opt calculation and the second is the freq analysis, G98 is not able
to read in the optimized wf using guess=read (failures to project some
orbitals), and starts with the default guess, which of course finally
converges to the wrong (instable) wavefunction.

Does anybody have a suggestion how I can do a frequency analysis on the
stable wf ?

Thanks in advance,
Theo de Bruin.

PS. I found in the archives that Tim Geo (23 Feb 2001) posted I similar
problem, but I could not find any replies to his questions.