Natural J-Coupling Analysis (NJC)
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Reference
S. J. Wilkens, Ph.D. Thesis (University of Wisconsin, Madison, 2001);
S. J. Wilkens, W. M. Westler, J. L. Markley, and F. Weinhold, J. Am. Chem. Soc. 123, 12026-12036 (2001).
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Notes
NJC analysis displays localized NBO/NLMO contributions to NMR J-coupling (nuclear spin-spin coupling), as evaluated by finite-field Fermi contact perturbation technique in the G9X program system. Separate UHF "field" perturbation calculations must be performed for each coupled nucleus, as illustrated in the Sample Input for vicinal J[H(2),H(6)] coupling in the formamide molecule. (See NBO 6.0 Manual, pp. B147-153.)
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Sample Input (G9X)
%chk=h2ncho
# uhf/3-21g pop=nboread field=f(2)200
formamide (b3lyp/6-311++g** geometry)
0 1
H -1.9085 0.4209 0.0000
H -1.1881 -1.1611 0.0000
N -1.0845 -0.1573 0.0000
C 0.1630 0.3867 0.0000
O 1.1963 -0.2463 0.0000
H 0.1402 1.4923 0.0000
$NBO file=amide_2 njc $END
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%chk=h2ncho
# uhf/3-21g pop=nboread field=f(6)200 guess=read geom=allcheckpoint
$NBO file=amide_6 njc print=0 $END