Natural Chemical Shielding (NCS) Analysis
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Reference
J. A. Bohmann, T. C. Farrar, and F. Weinhold, J. Chem. Phys. 107, 1173-1184 (1997).
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Notes
NCS is currently enabled only for G9X host systems. The "nmr" keyword should be included with "IOP(10/46=1)" parameter on the route card to invoke chemical shielding calculations with NCS analysis. The illustrated default NCS analysis displays only the isotropic shieldings (localized and delocalized contributions) to each nucleus. Other NCS keyword options display chemical shielding anisotropy (CSA), full shielding tensor, unperturbed (field-free, diamagnetic) and induced (field-dependent, paramagnetic) contributions, or other user-selected output (see NBO 6.0 Manual, pp. B130-138).
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Sample Input
#rhf/3-21g pop=nboread nmr iop(10/46=1)
RHF/3-21G GIAO chemical shieldings for idealized methylamine
0 1
C
N 1 1.47
H 1 1.09 2 109.4712
H 1 1.09 2 109.4712 3 120.
H 1 1.09 2 109.4712 3 -120.
H 2 1.01 1 109.4712 4 180.
H 2 1.01 1 109.4712 5 180.
$nbo ncs $end