Paramagnetic Effects#
Fast-relaxing electrons can have a variety of effects on NMR spectra. First, the relaxation of the electron acts a stochastic field on the nucleus via the hyperfine coupling, inducing paramagnetic relaxation enhancement (PRE). Second, while electron relaxation removes splittings on the nucleus resulting from hyperfine couplings, the electronic \(\alpha\) and \(\beta\) states are not equally populated, so that the nuclear resonance frequency shifts. This is known as the contact (isotropic hyperfine) or pseudo-contact (dipolar hyperfine) shift. We show how to simulate these effects here.