Nuclear magnetic resonance nuclei spin angular momentum

When placed in a static magnetic field of flux density B0, a nucleus may undergo nuclear magnetic resonance (NMR) [1-5] if it possesses an angular momentum p. This angular momentum is referred to as nuclear spin. The component of p in the direction of B0 (Fig. 1.1), denoted as p0, can only take on values which are half-integral or integral multiples m of hj2 n ... 

The basis of nuclear magnetic resonance spectroseopy lies with the property of a nucleus known as its spin. The classical picture is that of a spherical atomic nucleus rotating about its nuclear axis. Quantum mechanies describes this angular momentum F as a quantized property defined by the nuclear spin quantum number I ... 

The application of resonance that we describe here depends on the fact that electrons and many nuclei possess spin angular momentum (Table 13.1). An electron in a magnetic field can take two orientations, corresponding to nis = +j (denoted a or T) and nis=- (denoted p or >1). A nucleus with nuclear spin quantum number I (the analog of s for electrons and that can be an integer or a half-integer) may take 27-1-1 different orientations relative to an arbitrary axis. These orientations are distinguished by the quantum number mj, which can take on the values nti=I, 7-1,..., -7. A proton has 7= (the same spin as an electron) and can adopt either of two orientations (mi = + and— ). A N nucleus has 7=1 and can adopt any of... 

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