Nuclear magnetic resonance chemical independence

First experimental observations of the nuclear magnetic resonance (NMR) phenomenon were made in 1946 independently by groups working under Bloch (7) at Stanford and Purcell 112) at Harvard. For this discovery, these two physicists jointly were awarded the Nobel prize in physics in 1952. The experimental and theoretical aspects of nuclear magnetic resonance (NMR) have been developed rapidly so that today it is an indispensable technique for the investigation of a wide variety of chemical and physical phenomena. 

Analyses of Pitch. Modern analytical facilities of high-pressure liquid chromatography, gel permeation chromatography, an(j 1 nuclear magnetic resonance and mass spectrometry, associated with 1R and UV spectroscopy enable a total molecular constituent analysis of pitch composition to be obtained. The use of such information could then possibly be the route to prediction of pitch quality on carbonization. It would appear that such an approach would not be successful (ignoring the cost factor for such detailed analysis). The pitch cannot be considered as an assembly of molecules which pyrolyse independently of each other. The pitch carbonizes as a multi-phase system and experience today would indicate the impossibility of predicting all interactions, physical and chemical. 

Today the most useful chemical instrument is probably the nuclear magnetic resonance (NMR) spectrometer. Magnetic resonance imaging (MRI), vital in modern medicine, is derived from NMR. In late 1945, a physics group at Stanford, led by Felix Bloch (1905-83) (with William W. Hanson [1909-49] and Martin W. Packard), and one at Harvard, led by Edward M. Purcell (1912-97) (with Henry C. Tbrrey [1911-99] and Robert V. Pound [1919- ]), independently discovered the phenomenon of nuclear magnetic resonance. In order to manifest NMR an atomic nucleus must have nonzero nuclear spin. Of the roughly 100 stable isotopes that have nonzero nuclear spin, H, present in the vast majority of... 

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