From NWChem
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Gets Around
Threads 17
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| 6:57:38 AM PST - Thu, Nov 24th 2011 |
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The reason seems to be that you calculate singlet with Hartree-Fock for (assumed in dft part) doublet.
Count the electrons in the system and set the correct multiplicity.
For Hartree-Fock:
http://www.nwchem-sw.org/index.php/Hartree-Fock_Theory_for_Molecules#Wavefunction_type
for dft with:
http://www.nwchem-sw.org/index.php/Density_Functional_Theory_for_Molecules#ODFT_and_MULT_-...
In my impression (i may be wrong - don't know your system)
doing initially Hartree Fock geometry optimization and/or hybrid DFT is an overkill.
Maybe try just with PBE, and refine your results with PBE0 later.
This will offer you also a possibility to check dependence of your results on functional.
Note also that sometimes non-physical systems show convergence problems.
Or problems could be related to the basis set you use, maybe try ECP's (http://www.nwchem-sw.org/index.php/ECP)?
Check the example in the Nwchem source:
QA/tests/cu2_m06-l/cu2_m06-l.nw
I don't know what properties you are interested in, but the tiny 6-311G/6-31Gs basis will give you error of tenths of kcal/mol
in atomization energy of a medium/large (~50 atoms) Vanadium complex.
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