Nuclear magnetic shielding tensor

Table III Nuclear Magnetic Shielding Tensors (in ppm) for Group 13 Nuclei of Several Diatomic Molecules1...

Another important extension of the theory concerns NMR chemical shift. Yamazaki et al. proposed a theory for computing the chemical shift of solvated molecules [17]. The nuclear magnetic shielding tensor o-x of a nucleus X can be represented as a mixed second derivative of the free energy A with respect to the magnetic field B and the nuclear magnetic moment mx ... 

The first term, cr0(T), is a statistical average of the nuclear magnetic shielding tensor over all possible orientation of the molecule in the magnetic field and is different for the isotopomers. Theoretical aspects of isotope shifts were covered by Jameson and Osten.7... 

Calculation of nuclear magnetic shielding tensors for embedded molecules... 

Fig. 7a, b The relationship between the distance d between the sulfur and the carbon in the P=S H-C and the P-S- H-C units and the values of the principal elements of the P nuclear magnetic shielding tensors calculated by the DPT GIAO method... 

In order to demonstrate how a term proportional to arises in the relativistic theory, and to demonstrate how simple the relativistic theory really is, we will consider a textbook example the nuclear magnetic shielding tensor. In this case, we have... 

The GIAO method is used in conjunction with analytical derivative theory in this approach the magnetic field perturbation is treated in an analogous way to the perturbation produced by changes in the nuclear coordinates. In this framework, the components of the nuclear magnetic shielding tensor are obtained as ... 

Simulated C NMR shifts of polymers were also obtained from the other SCF calculations of B3LYP/6-31+G(d,p) basis using coordination of the model molecules at the second geometry optimization, in order to gain the nuclear magnetic shielding tensors. 

Final expression of the nuclear magnetic shielding tensor can be obtained... 

W. Scheubel, H. Zimmermann, U. Haeberlen, O quadrupole coupHng and nuclear magnetic shielding tensors in benzophenone, J. Magn. Reson. 63 (1985) 544. 

H. Fukui. Relativistic calculation of nuclear magnetic shielding tensor induding two-electron spin-orbit interactions. J. Chem. Phys., 125 (2006) 164106. 

A. D. Buckingham andS. M. Malm, Mol. Phys., 22, 1127 (1971). Asymmetry in the Nuclear Magnetic Shielding Tensor. 

Magnetizability and nuclear magnetic shielding tensors from electronic current density... 

---