SAPT2+(3)dMP2 unspecified charge

SAPT
1

Dear all,
I am having a problem regarding the SAPT calculation of this ion-pair/Non-covalent complex between CH2 singlet and FCl molecule.
The optimized geometry suggests that an ion-pair interaction is favoured (The Hirschfeld charge on F =~-0.5 ).

So, Can I calculate the interaction energy (components too) where I consider the interaction is supposed to be NCI. Like this input,

memory 24 gb
molecule {
0 1
	C   0.81152768710445     -0.00231702308990     -0.10149612929764
	H   0.44399116999178     -0.95955966438593     -0.43858252148521
	H   0.45295099235336      0.92728254984488     -0.51657034363772
--
0 1
	Cl  2.14622835902034      0.02748393927106      0.77306918669289
	F   3.77484479153005     -0.01954380164011     -0.17986219227232

no_reorient
symmetry c1
units angstrom
}
set globals {
	basis aug-cc-pvtz
	guess sad
}
energy ('sapt2+(3)dMP2')

This results in total IE as ~-91 kcal/mol

However, If I use another input to calculate the energy (components) of the ion-pair just by modifying the fragments in the input as,

memory 24 gb
molecule {
0 1
	C   0.81152768710445     -0.00231702308990     -0.10149612929764
	H   0.44399116999178     -0.95955966438593     -0.43858252148521
	H   0.45295099235336      0.92728254984488     -0.51657034363772
  	Cl  2.14622835902034      0.02748393927106      0.77306918669289
--
0 1
	F   3.77484479153005     -0.01954380164011     -0.17986219227232

no_reorient
symmetry c1
units angstrom
}
set globals {
	basis aug-cc-pvtz
	guess sad
}
energy ('sapt2+(3)dMP2')

Is it correct method? If it is, I am getting an error,

c: [0]
fc: [0.0]
fc: [0.0]
m: [1]
fm: [1]
fm: [1]
Traceback (most recent call last):
File “/home/prasanta/psi4conda/bin/psi4”, line 287, in
exec(content)
File “”, line 32, in
File “/home/prasanta/psi4conda/lib//python3.6/site-packages/psi4/driver/molutil.py”, line 250, in geometry
geom, enable_qm=True, missing_enabled_return_qm=‘minimal’, enable_efp=True, missing_enabled_return_efp=‘none’)
File “/home/prasanta/psi4conda/lib//python3.6/site-packages/qcelemental/molparse/from_string.py”, line 267, in from_string
**molinit,
File “/home/prasanta/psi4conda/lib//python3.6/site-packages/qcelemental/molparse/from_arrays.py”, line 127, in from_input_arrays
verbose=1,
File “/home/prasanta/psi4conda/lib//python3.6/site-packages/qcelemental/molparse/from_arrays.py”, line 386, in from_arrays
verbose=verbose,
File “/home/prasanta/psi4conda/lib//python3.6/site-packages/qcelemental/molparse/chgmult.py”, line 501, in validate_and_fill_chgmult
c_final, fc_final, m_final, fm_final = reconcile(cgmp_exact_c, cgmp_exact_fc, cgmp_exact_m, cgmp_exact_fm)
File “/home/prasanta/psi4conda/lib//python3.6/site-packages/qcelemental/molparse/chgmult.py”, line 491, in reconcile
raise ValidationError(err)

qcelemental.exceptions.ValidationError: Inconsistent or unspecified chg/mult: sys chg: None, frag chg: [0.0, 0.0], sys mult: None, frag mult: [1, 1]

Printing out the relevant lines from the Psithon --> Python processed input file:
0 1
F 3.77484479153005 -0.01954380164011 -0.17986219227232
no_reorient
symmetry c1
units angstrom
–> “”")
core.IO.set_default_namespace("")
core.set_global_option(“BASIS”, “aug-cc-pvtz”)
core.set_global_option(“GUESS”, “sad”)
energy (‘sapt2+(3)dMP2’)

Please Help on where I am making the mistake, can I use fraction charge?
Thank You

2

This error has nothing to do with SAPT and is a consequence of your specified molecules being unphysical. You specify that these are two neutral singlet on the 0 1 line - charge 0 and spin multiplicity 1. Psi realizes that your two “monomers” don’t have the right number of electrons for this and tells you “Inconsistent or unspecified chg/mult” because your charge and multiplicity are inconsistent.

That said, I don’t understand why you want to divide your system like this. SAPT is designed for noncovalent interactions. If you want to “decompose” the energy of your Cl-F in the presence of carbene, what you’re looking for is closer to F/I-SAPT.

3

Yes @jmisiewicz, I was trying blind with SAPT and needed some advice.
My idea was to compare the interaction strength (+ component) when the bond critical points (3,-1) are between Cl and C in one case; and Cl and F in other case. Lets see what I can get from F/I-SAPT .