- The Resonance Condition

The Resonance Condition

Consider an isolated nucleus in a steady magnetic field $H_{_{0}}$. The magnetic field breaks the symmetry of free space and defines a particular spatial direction. Suppose that the nucleus possesses an intrinsic "spin" with spin number $I>0$ so that it has a magnetic moment. The nucleus will have different energy states depending on the magnitude and direction of the nucleon's magnetic moment.

We know from quantum mechanics that (on small enough scales) energy appears in discrete bits ( $\hbar$ shows its face ).

We can define $\mu$ as the maximum measurable component of the magnetic moment.