Open-shell SAPT0 computation

1

Hello Everyone,

I have a question about open-shell SAPT computation in manual advanced example.

I am running below input then I meet the error massege:
RuntimeError:
Fatal Error: This is a RHF SAPT constructor. Pair those electrons up cracker!

my input (same manual):

molecule {
0 2
O 0.000000 0.000000 0.000000
O 0.000000 2.503900 0.000000
H 0.000000 -0.424700 -1.839500
–
0 1
O 0.000000 0.000000 6.000000
H 0.000000 1.431500 4.890600
H 0.000000 -1.431500 4.890600
units bohr
symmetry c1
no_reorient
no_com
}

dimer = psi4.get_active_molecule()

set {
reference uhf
scf_type df
basis cc-pVDZ
df_basis_sapt cc-pVDZ-ri
guess sad
}

dimer = psi4.get_active_molecule()

set df_ints_io save
psi4.IO.set_default_namespace(‘dimer’)
Edim, wfn_dimer = energy(‘scf’,molecule=dimer,return_wfn=True)
set df_ints_io load

monomerA = dimer.extract_subsets(1,2)
psi4.IO.change_file_namespace(97, ‘dimer’, ‘monomerA’)
psi4.IO.set_default_namespace(‘monomerA’)
set {
stability_analysis follow
}
EmonA, wfn_monA = energy(‘scf’,molecule=monomerA,return_wfn=True)

monomerB = dimer.extract_subsets(2,1)
psi4.IO.change_file_namespace(97, ‘monomerA’, ‘monomerB’)
psi4.IO.set_default_namespace(‘monomerB’)
set {
stability_analysis none
}
EmonB, wfn_monB = energy(‘scf’,molecule=monomerB,return_wfn=True)

psi4.IO.change_file_namespace(97, ‘monomerB’, ‘dimer’)
psi4.IO.set_default_namespace(‘dimer’)

psi4.sapt(wfn_dimer,wfn_monA,wfn_monB)

So I am beginner for psi4, i don’t know how to solve this problem… very happy to help me…

Best regards

omert

2

Hmm, a open shell SAPT0 computation should look more like the following:

molecule {
     0 2
     C 0.000000  0.000000  0.000000
     N 0.000000 0.000000  2.21
     --
     0 1
     Ne 0.000000 0.000000 -6.410228688
     units bohr
     symmetry c1
     no_reorient
     no_com
}

set {
reference rohf
scf_type     df
guess        sad
basis         jun-cc-pVDZ
df_basis_scf  aug-cc-pVDZ-jkfit
df_basis_sapt aug-cc-pVDZ-ri
}

energy('sapt0')

Where is your example in the manual?

3

@dgasmith, it’s here. Needs at least a basis set defined and perhaps some other updates. I got sidetracked.