Dear guys,
I am trying to set up a case for a CASSCF calculation with Psi4, and so far it looks intriguing. I am using a test system and the input file like this one:
molecule{
TI -0.0150616760 0.0005223151 -0.0088460157
O 1.6619541149 -0.1748776542 -0.6477026083
O -0.5863580705 1.6951366408 -0.2155285424
O 0.0386116105 -0.4398317741 1.7395629568
O -1.1457134213 -1.0938528281 -0.8958503769
H 2.2389860821 0.4859383075 -1.0298068211
H -0.7144606180 2.3742027551 0.4467927151
H 0.8116342000 -0.6233596016 2.2733914551
H -1.1195710325 -2.0485566872 -0.9597483836
}
set basis cc-pVDZ
set frozen_docc [ 27 ]
set active [ 4 ]
set num_roots 4
set mcscf_maxiter 60
en, wfn = energy('casscf', return_wfn=True)
molden(wfn, 'wfn.molden')
This is a state-specific run, what is confirmed by: STATE AVERAGE = 0(1.00) in the output. In addition I find the following lines:
==> MCSCF root 0 information <==
MCSCF Root 0 energy = -1150.426419689984868
Active Space Natural occupation numbers:
A 1.999216 A 1.994734 A 0.005262
A 0.000788
and:
==> MCSCF root 1 information <==
MCSCF Root 1 energy = -1149.646634938335183
Active Space Natural occupation numbers:
A 1.999601 A 1.016189 A 0.983873
A 0.000337
If I add AVG_STATES = [0,1] to the input file, the convergence is slightly more difficult and the output says: 0(0.50) 1(0.50). So far so good. But in that case, shouldnt the occulation numbers be close to 2.0, 1.5, 0.5, 0.0 ? Instead I get the same (almost) values as for the state-specific run…
Can someone please explain?
Cheers,
Bartek