The NMR relaxation time T 1 was calculated using our freely available analysis package NMRforMD . For brevity, only essential details are given here, more information about the method can be found in the original paper by Bloembergen, Purcell, and Pound , as well as in Refs. . In essence, T 1 can be related to autocorrelation functions of fluctuating magnetic dipole-dipole interactions of the form