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Re^3: MCSCF interpretation

Alex Granovsky


as to your question I think it is more important to use the same
orbitals and Fock operators in both XMCQDPT2 computations.

This can be done as follows. You need to run state-averaged
MCSCF averaging over doublets and quartet, and specify mplevl=2.
You need to add the following to the $mcscf group:

 $mcscf iforb=1 canonc=1 $end

and specify the following in the $xmcqdpt group

 $xmcqdpt iforb(1)=-1,1,1 mult=2 nstate=... $end

This will perform computations for doublets.

Then you need rerun computations for quartets:

 $mcscf iforb=1 canonc=1 $end
 $xmcqdpt iforb(1)=-1,1,1 mult=4 nstate=... $end

The $xmcqdpt iforb(1)=-1,1,1 directive forces XMCQDPT2 code
to use orbitals and effective Fock operators generated at the
MCSCF step while $mcscf iforb=1 canonc=1 options direct MCSCF
to produce state-averaged semi-canonical MOs.

Hope this helps.

Kind regards,
Alex Granovsky

On Thu Jan 23 '14 11:37pm, Pavlo Solntsev wrote

>Thank you for a quick answer. One more questions about the size of Hef in XMCQDPT. If i have SA-MCSCF solution over two doublets, do i need to examine Hef with size more than 2, by using nstate=n ?

>If i have quartet state very close to the second doublet, which is very close to the ground doublet. How do you think, is it good approach to do SS over two doublets and one quartet and then run XMCQDPT for doublets and quartets. In this case, for quartets i have Hef = 1. I am going to check the effect of the triplet state on the reference MCSCF. Maybe you have seen this situation before.

>On Thu Jan 23 '14 11:14pm, Alex Granovsky wrote
>>Dear Pavel,

>>this expansion corresponds to "-MCHF- OPTIMIZED ORBITALS".

>>Kind regards,
>>Alex Granovsky
>>On Thu Jan 23 '14 9:33pm, Pavlo Solntsev wrote
>>>Dear friends.

>>>I have a small question i would like to clarify. After a MCSCF wave function has been converged i have all states and their composition. For example:

>>>       ALPHA        |       BETA         | COEFFICIENT
>>> 111111111111111110 | 111111111111111010 |  -0.6988141
>>> 111111111111110111 | 111111111111110011 |  -0.5277073
>>> 111111111111111011 | 111111111111110110 |  -0.3496834
>>> 111111111111110111 | 111111111111111010 |  -0.1966670
>>> 111111111111111110 | 111111111111110011 |  -0.1530164
>>>To understand the nature of all major configurations that contribute to this state i need to analyze MO. What MO should i look at? Natural MO after MCSCF minimization? Any comments and suggestions would be very helpful.


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