[molpro-user] Analysis of CAS failure through microiterations

[Dr Seth Olsen]

Hi Molpro-Users,

I've attached the MULTI output with microiterations.  I've been having
big trouble with a CASSCF failure, and I'm trying to determine the
cause.  However, the microiteration output is extensive and I'm not sure
what I'm looking for.  Is there anyone on the list with the expertise to
tell me what might be going wrong?  

I've noticed that the last energy change is positive.  This usually
seems to freak MolPro out and cause it to give up the optimization. 
MolPro does seem particularly sensitive in this regard.  Can something
be set in the program to encourage it to soldier on for a little longer?
 The calculation is not small (26 atoms, ~250 basis fns., 12/11 active
space, 126 electrons).  I've been hacking at this one for quite a while
now and varying the step size, trust radii, and turning off second order
CASSCF for the first few iterations etc.  None of this seems to matter.

Can someone with more expertise explain what the conditions are under
which MolPro gives up the ghost in a CASSCF calculation?

Cheers,

Seth  



 

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Dr Seth Olsen, PhD
Postdoctoral Fellow, Biomolecular Modeling Group
Centre for Computational Molecular Science
Chemistry Building,
The University of Queensland
Qld 4072, Brisbane, Australia

tel (617) 33653732
fax (617) 33654623
email: s.olsen1 at uq.edu.au
Web: www.ccms.uq.edu.au 

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