Magnetic moment nuclides

Nuclide Natural abundance, % Spin I Sensitivity at constant field relative to NMR frequency for a 1-kG field, Mffz Magnetic moment J-T-1 Electric quadrupole moment Q, 10 m ... 

The angular momentum L has associated with it a magnetic moment /z. Both are vector quantities and they are proportional to each other. The proportionality factor y is a constant for each nuclide (i.e. each isotope of each element) and is called the gyromagnetic ratio, or sometimes the magnetogyric ratio. The detection sensitivity of a nuclide in the NMR experiment depends on y nuclides with a large value of y are said to be sensitive (i.e. easy to observe), while those with a small y are said to be insensitive. 

Nuclides with spin 7=0 therefore have no nuclear magnetic moment. Two very important nuclei, the isotope of carbon and the isotope of oxygen, belong to this class of nuclides—this means that the main building blocks of organic compounds cannot be observed by NMR spectroscopy. 

For most nuclides the nuclear angular momentum vector L and the magnetic moment vector (L point in the same direction, i.e. they are parallel. However, in a few cases, for example, N, they are antiparallel. 

Fig. 3. Mossbauer spectrum resulting from a magnetic liyperfine interaction between electron paramagnetic moment and Mossbauer nuclide nuclear magnetic moments...

The refinement of °Be measurements and the fact that its concentrations can also be measured in ice cores for the last several hundred thousand years allows the evaluation of its production variations over time as shown by Frank et al. (1995). They normalized the °Be concentration with respect to °Th to accommodate regional focusing of the two nuclides as the result of particle scavenging in much the same way as He accumulation rate was calibrated (see discussion in next section). Sharma (2002) used this approach to show that the °Be flux changes, once corrected for the Earth s intrinsic magnetic moment changes. 

The table includes all stable nuclides of non-zero spin for which spin and magnetic moment values have been measured, as well as selected radioactive nuclides of current or potential interest. At least one isotope is included for each element through Z = 95 for which data are available. See Reference 1 for a complete listing of spins and moments. 

Nuclide Atomic mass Natural abundance (%) Nuclear spin I Nuclear magnetic moment fi... 

By far. the majority of nuclides with spin are quadrupolar nuclei (/ > 112). It should be remembered that for a spin I, there are 21 -r 1 energy levels and 21 allowed transitions. Of those with spin I = 1. H is by far the most popular. The magnetic moment of °H is a factor of 7 smaller than that of H. resuliing in a lower resonance frequency and much smaller homonuclear dipolar couplings. The... 

CaCd(CH3COO)4 6H2O the fine structure comes from two copper nuclides both having a nuclear spin of 3/2 and similar magnetic moments. The full detailed structure in a spectrum may not always be resolved and a broadening of lines is observed. For solutions, the dipolar coupling is averaged to zero so that ... 

Nuclide Type Abundance % Nuclear spin Magnetic moment p ... 

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