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Re^4: SA2-CAS(2,2) calculation with cistep=ALDET and ISPIN=0

Alex Granovsky
gran@classic.chem.msu.su


Dear Thom,
Dear Evgeniy,

the important option here is the logical varuable PURES in $DET group.
When set to .true. (the default value), it filters out states
of multiplicity specified in the $CONTRL group. In ypur case,
wstate would refer to singlet states only and should be specified
as follows:

 NSTATE=3 
 wstate(1)=1,1 

When set to .false. no filtering is performed so indeed wstate
should be specified as Thom already suggested. In addition, I'd
recommend to activate state tracking just in case (ntrack=3 in $MCSCF).

Hope this helps,
Alex


On Wed Mar 1 '17 0:11am, Thomas Pijper wrote
--------------------------------------------
>Dear Evgeniy,

>NSTATE merely selects the number of CI states to take into consideration. It does not specify which states to average over. Instead, the WSTATE keyword can be used for this.

>As an example, if the first three states are of the multiplicities [singlet, triplet, singlet] and you would like to average over the two singlet states, specify the following:

NSTATE=3 WSTATE(1)=1,0,1

>Hope this helps.
>
>
>Kind regards,
>Thom

>On Mon Feb 27 '17 9:38pm, GrEv wrote
>------------------------------------
>>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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