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Re^3: MCSCF for a large system.

Pavlo Solntsev
pavlo.solntsev@gmail.com


What i usually do is to run single point with one weighted state: wstate(1)=1,-0 and nstate=5 for example. Check carefully all states, what they are. If you see some low lying excited state, they may affect your ground state. Then you should include them into average. You may increase nstate if needed. Details, for SA-CASSCF described very well in manual. Some examples also available.

Pavlo.


On Thu Sep 11 '14 9:26pm, alex wrote
------------------------------------
>Dear Pavlo,
>Thanks for the comments. Could you please share your experience with a bit more details on how to weight the states which I want to consider? Does simple 1,1,1,... work in most cases or there is a better algorithm exists?
>Regards,
>Alex
>
>
>
>>From my experience, run first a job using say 5 states, but putting only first in wstate array (wstate(1)=1,-0). If you see states close to your ground state, they may affect your ground state and you should consider them by putting to the wstate array. However, geometry optimization for SA-CASSCF was discussed here. Do a search.
>>
>>How it is related to the active space?
>>
>>I afraid, there is no relationship.
>>
>>Every next step during a geometry optimization uses orbitals from previous. With good starting geometry and the correct active space it should not be a problem.
>>
>>relevant part of the output file would be very informative for this case.
>>
>>
>>Pavlo.
>


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