GrEv
grevgen13@gmail.com
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