Integer spins

Although MAS is very widely applied to non-integer spin quadnipolar nuclei to probe atomic-scale structure in solids, such as distinguishing AlO and AlOg enviromnents [21], simple MAS about a single axis caimot produce a completely averaged isotropic spectrum. As the second-order quadnipole interaction contains both... 

Finally, let us consider molecules with identical nuclei that are subject to C (n > 2) rotations. For C2v molecules in which the C2 rotation exchanges two nuclei of half-integer spin, the nuclear statistical weights of the symmetric and antisymmetric rotational levels will be one and three, respectively. For molecules where C2 exchanges two spinless nuclei, one-half of the rotational levels (odd or even J values, depending on the vibrational and electronic states)... 

Only integer and half-interger values ean range from j to -j in steps of unity. Speeies with integer spin are known as Bosons and those with half-integer spin are ealled Fermions. 

Boltzmann distribution statistical distribution of how many systems will be in various energy states when the system is at a given temperature Born-Oppenbeimer approximation assumption that the motion of electrons is independent of the motion of nuclei boson a fundamental particle with an integer spin... 

There are two possible cases for the wavefunction of a system of identical fundamental particles such as electrons and photons. These are the symmetric and the antisymmetric cases. Experimental evidence shows that for fermions such as electrons and other particles of half integer spin the wavefunction must be anti-symmetric with respect to the interchange of particle labels. This... 

The presence of low-lying excited levels can greatly increase the efficiency of the relaxation processes, especially in the case of paramagnetic centers with half-integer spins. 

B) Is there a central line If there is no central line, then there must be an even number of lines, which suggests an odd number of half-integer nuclei i.e., I = 1/2, 3/2, etc.), which would cause splitting of any center line arising from an even number of half-integral nuclei or any number of nuclei with integer spin (I = 1,2, etc). 

FIGURE 5.9 Effective g-values for half-integer spin systems in axial symmetry. The scheme gives the values for all transitions within the Kramer s doublets of S = nl2 systems assuming gmal = 2.00 and S S S B. 

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