[molpro-user] making start command valid in optg

[Valérie Vallet]

Dear Joachim,

We have tried the failsafe option in the casscf block, but this does not improve the CASSCF convergence along the IRC. 
Could you please modify the molpro code so that we can force the casscf step to restart from HF orbitals? 
Would it also be possible to offer the possibility to change the step size in the IRC calculation, since this may help improving the CASSCF convergence along the IRC?

Thanks a lot for your help,

Valérie

On Nov 20, 2011, at 5:33 PM, Hans-Joachim Werner wrote:

> Dear Valérie and Jacky,
> I will look at this. This was once changed to make sure that in geometry optimizations it always
> uses the same options and starting orbitals from the previous calculation, which is normally most
> sensible. I will make an option to disable this behavior. In the meantime you could try the 
> "FAILSAFE" option, which enables stricter convergence criteria. Perhaps that helps finding the correct
> solution.
> Best wishes
> Joachim
> 
> 
> -- 
> Prof. Hans-Joachim Werner
> Institute for Theoretical Chemistry
> University of Stuttgart
> Pfaffenwaldring 55
> D-70569 Stuttgart, Germany
> Tel.: (0049) 711 / 685 64400
> Fax.: (0049) 711 / 685 64442
> e-mail: werner at theochem.uni-stuttgart.de
> 
> 
> 
> Am 18.11.2011 um 16:22 schrieb Valérie Vallet:
> 
>> Dear MOLPRO users,
>> 
>> We are trying to run an IRC path at the CASSCF level, and we are facing a case where the automatic CASSCF calculation that uses previous CASSCF orbitals along the reaction coordinate converges to the wrong energy, that is an energy higher than the that one would obtain with a single point calculation using Hartree-Fock orbitals. 
>> 
>> We thus would like to force the CASSCF to use HF orbitals instead at each geometry steps. However, it seems that the optg keyword ignores "start" commands in the MCSCF step. Is there an option that allows us to force optg to read "start" instructions?
>> 
>> Thanks a lot for your help,
>> 
>> Valérie Vallet
>> 
>> 
>> 
>> ---
>> Valérie Vallet
>> Research assistant
>> Laboratoire PhLAM, CNRS UMR 8523
>> Université des Sciences et Technologies de Lille
>> Bât P5
>> F-59655 Villeneuve d'Ascq, France
>> Tel: +33 3 2033 5985
>> Fax: +33 3 2033 7020
>> E-mail: valerie.vallet at univ-lille1.fr
>> http://www.phlam.univ-lille1.fr/pub/f/themas/pcmt/
>> 
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>