Strong-field limit of a two-spin exchange spectrum
= Strong-field limit of a two-spin exchange spectrum
If the differential Zeeman <energy> $|w|=|\mu_0B(g_1-g_2)|$ greatly exceeds $|\Delta|$, the two mixed levels are $-\Delta/4\pm|w|/2+O(\Delta^2/|w|)$ and approach opposite-spin product states. Four energies are generically distinct. Equal signed moments have $w=0$, so that block remains singlet/triplet rather than being unmixed by a stronger field.