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Re^3: Question on CSFs: the same CSFs in the WF expansion

Alex Granovsky
gran@classic.chem.msu.su


Dear Evgeniy,

add

 $drt nprt=2 $end

to your input.

Hope this helps,
Alex




On Sun May 8 '16 3:33pm, GrEv wrote
-----------------------------------
>Dear Alex,

>Thanks for your response.
>Just curious, is it possible to retrieve (with a print option) the spin configuration of each (same) orbital configuration?

>Best regards,
>Evgeniy

>On Fri May 6 '16 10:01pm, Alex Granovsky wrote
>----------------------------------------------
>>Hello,

>>below, "OCCUPANCY" means orbital configuration.

>>There exist CSFs with identical orbital configuration but with
>>different spin coupling. This is what you see in your output.

>>Kind regards,
>>Alex Granovsky
>>
>>
>>On Fri May 6 '16 8:59pm, GrEv wrote
>>-----------------------------------
>>>Hello,

>>>I wonder how to interpret the same CSFs (configurations) in the WF expansion in a CASSCF calculation. In particular, I have the following expansion for a singlet (excited) state:

>>>     CSF      COEF    OCCUPANCY (IGNORING CORE)
>>>...
>>>    67033   -0.060115  222211101000
>>>    74594   -0.114228  222211101000
>>>...
>>>    88706    0.066301  222121110000
>>>   118407    0.162652  222121110000
>>>...

>>>As can be seen, CFSs 67033 and 74594 as well as 88706 and 118407 look the same, though contribute with different coefficients. I guess these are let's say \alpha \alpha \beta \beta and \alpha \beta \beta \alpha configurations, i.e. double-excitation of the parallel and anti-parallel by spin electrons (like in MP2). Is it possible to say which of the same configurations corresponds to excitation of parallel and anti-parallel electrons?
>>>
>>>
>>>Best regards,
>>>Evgeniy


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