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Re^2: SA2-CAS(2,2) calculation with cistep=ALDET and ISPIN=0

GrEv
grevgen13@gmail.com


Thanks for your response. Yes I set NSTATE to 2, because I want to do SA2-CASSCF(2,2) averaging over two singlet states S0 and S1. But this seems to be not possible with cistep=guga, because ISPIN doesn't work here, and without ISPIN one cannot select two singlet states, as the second state (after S0) is a triple.

Best regards,
Evgeniy

On Sat Feb 25 '17 10:29pm, Alex Granovsky wrote
-----------------------------------------------
>Hello,

>the ISPIN option works only with iterative Davidson eigensolver.

>With CASSCF(2,2) and alike, Hamiltonian matrix is tiny and is
>diagonalized directly using one of available diagonalization
>routines rather than iteratively, so that the ISPIN option is
>ignored.

>My guess is that you set NSTATE to 2 and got two states,
>namely lowest singlet and lowest triplet. This is why program
>complains (as it needs two singlet states). Use NSTATE=3 and
>you'll get two singlets and a triplet state.

>Kind regards,
>Alex Granovsky
>
>
>
>
>On Fri Feb 24 '17 2:18pm, GrEv wrote
>------------------------------------
>>Hello,

>>I have a question related to a SA2-CAS(2,2) calculation using cistep=ALDET and ISPIN=0.
>>I am interested in two singlet states, S0 and S1. Even with NSTGSS=4
>>the calculation crashes with the error:

>> ***** ERROR *****
>> THIS RUN FOUND    1 CI EIGENVECTORS WITH S= 0.00,
>> BUT YOU REQUESTED STATE AVERAGING OF    2 ROOTS.
>> PLEASE EXAMINE YOUR CHOICE OF -NSTATE- INPUT DATA.

>>So, I wonder if cistep=ALDET can be used in such a case, or only cistep=GUGA works here?

>>Best regards,
>>Evgeniy


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