[molpro-user] CASPT2 convergence problem

[Yang Yang]

Hi, Dear Molpro Community,

I'm trying to solve the lowest 3 excited states with a particular symmetry and spin in a CASPT2 calculation. The previous state-averaged CASSCF calculation always converges successfully. However, only the first excited state in the CASPT2 calculation can converge. If I include the second or/and third state(s) in a multi-state CASPT2 or solve the second/third state individually, then there is no convergence.

I have tried to use different CASSCF reference states as the initial guess, modify the level shift or increase the iteration number. None worked so far. Any other things i may try to help the convergence?

Thanks a lot!

Sincerely

yang


 		 	   		  
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