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Re^4: MCSCF for a large system.


Thanks Pavlo! I am realizing the importance of adding the states but still can’t understood how to combine them appropriately. Lets consider (typical) situation of bond breaking with two states of interest: #1 ground only (COEF=0.8) and #2 a combination of 3 excitations - one is the desired biradical (COEF=0.6) and a two ‘others’ (COEF=0.2 and COEF=0.1). What weight (WSTATE values) would you use for the two states? Or at least what the strategy is better from your experience WSTATE(1)=1,1 or WSTATE(1)=0.6,0.8 or WSTATE(1)=0.9,0.8?

On Fri Sep 12 '14 5:21am, Pavlo Solntsev wrote
>What i usually do is to run single point with one weighted state: wstate(1)=1,-0 and nstate=5 for example. Check carefully all states, what they are. If you see some low lying excited state, they may affect your ground state. Then you should include them into average. You may increase nstate if needed. Details, for SA-CASSCF described very well in manual. Some examples also available.


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