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

Alex Granovsky


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

>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:

>    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,

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