Solid-state nuclear magnetic resonance
Solid-state nuclear magnetic resonance (ssNMR) is a spectroscopy technique used to characterize atomic-level structure and dynamics in solid materials. ssNMR spectra are broader due to nuclear spin interactions which can be categorized as dipolar coupling, chemical shielding, quadrupolar interactions, and j-coupling.
Source: Wikipedia — Solid-state nuclear magnetic resonance (CC BY-SA 4.0)