B. Jagadeesh et al., PROTON NMR INVESTIGATION OF MOLECULAR-DYNAMICS IN [N(CH3)4]3 SB2BR9 (TEMABA), Journal of physics and chemistry of solids, 54(5), 1993, pp. 527-531
Cation dynamics in tris (tetra-methylammonium) nonabromodiantimonate,
which shows structural phase transitions, are studied through proton s
pin lattice relaxation measurements (at two Larmor frequencies) and li
ne width measurements. Results show a clear signature of a phase trans
ition at 189 K and the existence of dynamically inequivalent methyl gr
oups. The dynamics of the cation as a whole are found to be less hinde
red above this temperature. Activation energies associated with the dy
namics of the cations and methyl groups are calculated.