# Read wavefunction of different spin multiplicity in CASSCF

Hello,

Suppose I have a quintet CASSCF wavefunction, how can I read the orbitals of this wavefunction and use them in a triplet CASSCF calculation?

This is an example. I try to redefine the value S value in DETCI, but the second CASSCF calculation is just a duplication of the first one.

Thank you.

``````molecule {
0 5
O          0.00000        0.00000        0.11779
H          0.00000        0.75545       -0.47116
H          0.00000       -0.75545       -0.47116
}

basis {
assign o def2-SVP
assign h def2-SVP
}

set {
reference       rohf
scf_type        pk
nat_orbs        True
restricted_docc [1, 0, 0, 0]
active          [4, 1, 2, 3]
REFERENCE_SYM   1
}

scf_energy, scf_wfn = energy('scf', return_wfn=True)
casscf_energy, casscf_wfn = energy('casscf', return_wfn=True)

set {
S               1
REFERENCE_SYM   1
}

casscf_energy2, casscf_wfn2 = energy('casscf', return_wfn=True, ref_wfn=casscf_wfn)
``````

First CASSCF
==> Starting MCSCF iterations <==

``````        Iter         Total Energy       Delta E   Orb RMS    CI RMS  NCI NORB
@MCSCF  1:    -75.293777725918   -2.9805e-02  6.48e-03  3.39e-07    8    1  Initial CI
Warning! Maxstep = 0.51, scaling to 0.50
@MCSCF  2:    -75.311665906005   -1.7888e-02  5.08e-03  1.85e-06    8    1  TS
@MCSCF  3:    -75.318056417958   -6.3905e-03  2.49e-03  1.91e-06    8    1  TS
@MCSCF  4:    -75.320346614146   -2.2902e-03  1.48e-03  1.09e-06    8    1  TS, DIIS
@MCSCF  5:    -75.321214907858   -8.6829e-04  1.06e-03  5.83e-07    8    1  TS, DIIS
@MCSCF  6:    -75.321620304717   -4.0540e-04  1.09e-03  4.67e-07    9    1  TS, DIIS
@MCSCF  7:    -75.321734164172   -1.1386e-04  6.49e-04  8.40e-07    7    1  TS, DIIS
@MCSCF  8:    -75.321790737313   -5.6573e-05  1.91e-04  2.31e-07    8    1  TS, DIIS
@MCSCF  9:    -75.321799572911   -8.8356e-06  8.13e-05  1.14e-07    8    1  TS, DIIS
@MCSCF 10:    -75.321804575013   -5.0021e-06  3.84e-05  3.64e-08    9    1  TS, DIIS
@MCSCF 11:    -75.321806456819   -1.8818e-06  2.32e-05  2.70e-08    9    1  TS, DIIS
@MCSCF 12:    -75.321806888302   -4.3148e-07  7.79e-06  1.06e-08    9    1  TS, DIIS
@MCSCF 13:    -75.321806952407   -6.4105e-08  2.11e-06  5.77e-09    9    1  TS, DIIS

@MCSCF has converged!

@MCSCF Final Energy:  -75.321806952407229
``````

Second CASSCF
==> Starting MCSCF iterations <==

``````        Iter         Total Energy       Delta E   Orb RMS    CI RMS  NCI NORB
@MCSCF  1:    -75.321806952407   -5.7834e-02  2.11e-06  5.82e-07    8    1  Initial CI
@MCSCF  2:    -75.321806953738   -1.3311e-09  1.28e-06  1.06e-09    9    1  TS
@MCSCF  3:    -75.321806954574   -8.3612e-10  9.66e-07  7.94e-10    9    1  TS
@MCSCF  4:    -75.321806955131   -5.5665e-10  7.83e-07  6.82e-10    9    1  TS, DIIS

@MCSCF has converged!

@MCSCF Final Energy:  -75.321806955131024``````