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Re: XMCQDPT2 for ALDET state-averaged results

Andrei V Scherbinin

Hello Andrey,

There is a useful option INORB=1 in the $XMCQDPT group
that allows to read SOME converged orbitals from a $VEC
group, and pass immediately to the XMCQDPT computation.
(A complete $VEC including all virtuals must be given).

In particular, the user may read in the same MOs (say,
those resulting from the state-average ALDET CASSCF
calculation) in order to perform separate XMCQDPT runs
for different spin multiplicities (of course, no guarantee
that such a perturbation treatment always makes sense).

Best wishes,


On Fri May 28 '10 4:54pm, Andrey wrote
>I have performed state-averaged calculations by using CISTEP=ALDET. The density was averaged over two states, namely, singlet and triplet, with the same Sz=0. The problem is I cannot do XMCQDPT2 calculations for both states at once based on averaged density from above ALDET-calculations.
>I understand that these states should not be mixed in Heff. The idea was (and is) to estimate both states with the same quality. Because, if I do all calculations (CASSCF followed by MRPT) for each state separately as state-specific ones, I will get, strongly speaking, different quality of description for different states.

>Can someone help me to overcome this problem?

>thank you very much in advance!

[ This message was edited on Fri May 28 '10 at 8:54pm by the author ]

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