Dear all,
I’m a user of CASSCF with other packages, and I would like to switch to Psi4 using the DETCI module. I wanted to optimize the two lowest roots of the NO molecule (which is \Pi state, but I switched off symmetry). In NO molecule there are 7 doubly occupied orbitals and singly occupied degenerate \pi. So I want active space to consist of degenerate \pi orbitals (numbers 8 and 9). After successful initial ROHF calculations DETCI module calculates one energy and next produces NaN energies.
I’m using conda-installed psi4 (MacOS, Monterrey).
Here is my input:
`
molecule {
N
O 1 1.20
symmetry c1
}
set {
basis cc-pvdz
reference rohf
qc_module detci
RESTRICTED_DOCC [7]
ACTIVE [2]
NUM_ROOTS 2
}
casscf_energy = energy(‘casscf’)
`
Options and space information looks like:
==> Parameters <==
EX LEVEL = 1 H0 BLOCKSIZE = 1000
VAL EX LEVEL = 0 H0 GUESS SIZE = 1000
H0COUPLINGSIZE = 0 H0 COUPLING = NO
MAXITER = 12 NUM PRINT = 20
NUM ROOTS = 2 ICORE = 1
PRINT LVL = 1 FCI = YES
R CONV = 1.00e-07 MIXED = YES
E CONV = 1.00e-06 MIXED4 = YES
R4S = NO REPL OTF = NO
DIAG METHOD = SEM FOLLOW ROOT = 0
PRECONDITIONER = DAVIDSON UPDATE = DAVIDSON
S = 0.5000 Ms0 = NO
GUESS VECTOR = H0BLOCK OPENTYPE = HIGHSPIN
COLLAPSE SIZE = 1 HD AVG = EVANGELISTI
MAX NUM VECS = 26 REF SYM = AUTO
IOPEN = YES
EX ALLOW = 1
STATE AVERAGE = 0(1.00)
==> CI Orbital and Space information <==
Space Total A
Nso 28 28
Nmo 28 28
Ndocc 7 7
Nsocc 1 1
MCSCF Spaces
Frozen DOCC 0 0
Restricted DOCC 7 7
Active 2 2
Restricted UOCC 19 19
Frozen UOCC 0 0
==> Setting up CI strings <==
whereas MCSCF calculations looks like:
==> Starting MCSCF iterations <==
Iter Total Energy Delta E Orb RMS CI RMS NCI NORB
@MCSCF 1: -129.241795183825 -3.0462e-04 1.96e-04 3.51e-30 1 1 Initial CI
Warning! Maxstep = 3534292964.38, scaling to 0.50
@MCSCF 2: nan nan nan 0.00e+00 12 1 TS
@MCSCF 3: nan nan nan 0.00e+00 12 1 TS
@MCSCF 4: nan nan nan 0.00e+00 12 1 TS, DIIS
Thanks in advance for the answer!
Piotr