As shown in Figure , the 2 H quadrupolar pattern of alkanoate ligands on NCs can be divided into three contributions: a narrow peak with full-width-at-half-maximum (FWHM) of a few kHz, a partially-averaged pattern with 35 kHz splitting, and a Pake pattern with 120 kHz splitting. The narrow peak is attributed to the CD2 and CD3 units undergoing large-amplitude cone diffusion which can be considered as a free motion without the restriction by neighboring ligands. The 35-kHz Pake pattern is attributed to the CD2 units undergoing trans-gauche-gauche (tgg) rotation which is an indication of ligand-ligand packing under partial confinement . The 120-kHz Pake pattern is attributed to the rigid CD2 units that have a mobility slower than ~ 100 kHz. The slow mobility of CD2 may be due to two reasons, near the anchoring carboxylate at NC surface and/or bearing a stronger ligand-ligand interaction. It is expected that the inner CD2 units (closer to the carboxylate head group) have lower flexibility/mobility and the outer units (closer to the methyl tail group) have higher flexibility/mobility.