Le jeudi, 27 mar 2003, à 09:01 Europe/Paris, Kalju Kahn a écrit :
Hello,
I am fairly new to molpro and I am not sure if the problem I am having with cipt2 calculation of the exited state is a result of my limited understanding of the method or a program bug. I am running a cipt2 calculation on the third exited state of benzonitrile. The molecule has C2v symmetry and the exited state belongs to A1 irreducible representation. The A1 ground state calculation is successful and I can do RS2 calculations in the exited state after using level shifts around 0.15. The relevant portion of my cipt2 input looks like this: -------------------------------- basis,roos(3s2p1d/2s)
hf
multi occ,15,6,8,2 core,6,0,2,0 closed,15,0,8,0 wf,54,1,0
cipt2 occ,15,6,8,2 core,6,0,2,0 closed,15,0,8,0 wf,54,1,0 maxiter,80,100 state,1,3 refstate,1,3
I suppose that what you've experienced was a variational collapse of the MRPT2 wf of your 3rd exited state during your PT2 calculation.
Try to put :
state,3
instead of :
state,1,3 refstate,1,3
(the three first MRPT2 roots should be calculated at the same time, taking the three first MCSCF roots as refs.)
Best regards,
Benoît
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