I'm calculating the H-H J-coupling of the water molecule using the following input:
start job
geometry units angstroms
O 0.0 0.0 0.110812
H 0.0 0.783976 -0.443248
H 0.0 -0.783976 -0.443248
end
basis
O library cc-pvdz
H library cc-pvdz
end
dft
xc pbe96
grid lebedev
tolerances tight
odft
noio
end
property
spinspin 1 2 2
end
task dft property
Here is the J-coupling and its various terms in comparison to the ones obtained with Dalton and FHI-aims:
| | Fermi contact | Paramagnetic | Spin-dipole | Diamagnetic | Total |
| FHI-aims | 0.7096 | 8.1231 | 0.4637 | -7.8966 | 1.3997 |
| Dalton | 0.7149 | 8.1222 | 0.4646 | -7.8967 | 1.4050 |
| NWchem | -539.8454 | -28.6307 | -14.0512 | 225128.6878 | 224546.2 |
Full output is available here. As you can see, the numbers not only differ, but are clearly unrealistic. I tried with other functionals and with Hartree-Fock but the results are overall similar. Could somebody check the above input and tell me if there is a mistake?
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