Calculated vs Experimental Chemical Shift Tensors Using Different NMR Methods

2 Calculated vs Experimental Chemical Shift Tensors Using Different NMR Methods 

The vast majority of applications of GIPAW so far have focused on the ICS and the quadrupolar coupling (for nuclei with spin quantum number I 1/2), and there have been far fewer studies that have exploited interactions such as the CSA. This is mainly a result related to the difficulty in accurately measuring such interactions for all but the simplest systems, although developments in experimental methodologies will enable the determination of parameters across a wider range of increasingly complex systems. 

FIGURE 12.5 Quality of the data fitting as a function of for (a) QC tensor components Qqjh, i=x, y, z) and (b) O CST components obtained at 298 K. Correlations between experimental and CASTEP-computed (c) CST components and (d) QC tensor components for salicylic acid (open circles) and aspirin (closed circles). Adapted with permission from Ref. [46]. Copyright 2013, American Chemical Society. 

FIGURE 12.6 (a) Potential energy surface for thiophene ring rotation in ROY. The angles 

FIGURE 12.7 The calculated CSs for the phenyl ring selected carbons (a) C7 and (b) C13 as a function of coplanar angle. Adapted with permission from Ref. [49]. Copyright2006, American Chemical Society. 

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