Nuclear magnetic resonance frame

The different VCD spectra calculated for the NMR and X-ray structures demonstrate just how sensitive VCD is toward structural changes. It is premature, at this stage, to attempt to use VCD as a tool to distinguish or even judge the quality of either of the previously obtained structures. However, further computational efforts may well establish VCD as a complementary tool to NMR for the determination of solution conformation. VCD will certainly not challenge NMR in large molecules, where the superior resolution allows detailed structures to be derived. However, the much faster time frame of vibrational spectroscopy over nuclear magnetic resonance techniques allows distinct structures to be discerned when NMR measurements perceive little structure. 

Several physical methods have been employed to ascertain the existence and nature of ICs infrared (IR) absorption spectroscopy nuclear magnetic resonance (NMR) spectroscopy,14 including JH nuclear Overhauser effect (NOE) difference spectroscopy, H 2-D rotating-frame Overhauser effect spectroscopy (2-D ROESY),15 and solid-state 13C cross-polarization/magic angle spinning (CP/MAS) spectroscopy 16 induced circular dichroism (ICD) absorption spectroscopy 17 powder and singlecrystal X-ray diffraction 18 and fast atom bombardment mass spectrometry (FAB MS). 

It should be noted that all our considerations up to now have been made for the rotating frame. For the experimental investigation of the nuclear magnetic resonance, we are interested in the component of the magnetization which rotates with the frequency 0 in the laboratory frame and which is the response of the nuclear magnetic system to the rf-field at frequency <0. This component rotating with cu in the laboratory frame must be static in the rotating frame and must Ik perpendicular to the z-axis. Thus, the required response component is u (cf. Eq. (20) and see Fig. 5). 

J.J. Kweon, K.W. Lee, K.-S. Lee, C.E. Lee, Rotating-frame nuclear magnetic resonance study of the superprotonic conduction in LiH2P04, Sohd State Commun. 171 (2013) 5-7. 

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