Chemical shift tensors computational approaches

COMPUTATIONAL APPROACHES TO THE CALCULATION OF CHEMICAL SHIFT TENSORS IN SOLIDS... 

As described in Section 11, NMR chemical shifts can be computed as second derivatives [Eq. (6.8)]. With the development of analytic second derivative techniques for electron-correlated schemes [84], calculation of NMR chemical shifts thus became possible. In the last decade, a number of correlated approaches have been applied (together with appropriate measures for treating the gauge-origin problem) to the calculation of chemical shielding tensors, which has allowed its applications to several chemically interesting problems. 

Froteins, unlike crystalline tripeptides, do not easily lend to a plane-wave periodic approach. Computations that make use of molecular fragments remain useful in studying chemical shifts in these systems. Cai et al. sustain their exploration of isotropic chemical shifts and tensors in a recent study of protein GB3. Currently, protein backbone amide isotropic shifts are satisfactorily reproduced, but considerable differences are still... 

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