Magnetic shielding constants

Gauss, J., Stanton, J. F., 1996, Perturbative Treatment of Triple Excitations in Coupled Cluster Calculations of Nuclear Magnetic Shielding Constants , J. Chem. Phys., 104, 2574. 

The factor rr [9] is called the magnetic shielding constant for the nucleus i, and characterizes the chemical environment of that nucleus. The effective field experienced by the nucleus i follows from eqs. (1.38, 1.39) ... 

The magnetic shielding constant (eq. 1.39) arises from the influence of chemical effects on the Larmor frequency of a nucleus. It is described in terms of three additive contributions (eq. 3.2) ... 

Table 10 Representative calculations of 13C magnetic shielding constants relative to 13C in CH4 calculated using SCF perturbation theory and GIAO...

Table 3 Mulliken effective charges Z(e) and magnetic shielding constants a (ppm) of the atoms in the C60H36 and C6qH24 molecules and their MH4 endofullerenes3...

Figure 2 Magnetic shielding constants a (ppm) on H (a) and C (b) cage atoms and their Mulliken s effective charges (c) in MO C60H36(r) clusters.

Table 8 Magnetic shielding constants a (Ng) and a (C ) (ppm) in endofullerenes with Ng atoms and Ng4 clusters inside C60H3g (T) and C84 (Td) cages3...

Theoretical bases of continuum models including their mathematical formulation and numerical implementation have already been discussed in the previous chapter of this book. We have therefore restricted our review to the environment effects on the NMR observables, without going into the theory of continuum models. This contribution is divided into five sections. After the Introduction, the definitions of the NMR parameters are recalled in the second section. The third section is focused on methodological aspects of the calculation of the NMR parameters in continuum models. The fourth section reviews calculations of the solvent effects on the nuclear magnetic shielding constants and spin-spin coupling constants by means of continuum models, and the final section presents a survey on the perspectives of this field. 

J. Kongsted, C.B. Nielsen, K.V. Mikkelsen, O. Christiansen, K. Ruud, Nuclear magnetic shielding constants of liquid water Insights from hybrid quantum mechanics/molecular mechanics models, J. Chem. Phys. 126 (2007) 034510. 

M. Kubiszewski, W. Makulski and K. Jackowski, Intermolecular effects on spin-spin coupling and magnetic shielding constants in gaseous difluoromethane.. Mol. Struct., 2004, 704,211-214. 

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