1H and 2H Magic Angle Spinning Nuclear Magnetic Resonance Study of Phase Transition in KH3(SeO3)2 and Deuterated KD3(SeO3)2

Abstract

The chemical shifts and spin–lattice relaxation times T 1ρ in KH3(SeO3)2 and deuterated KD3(SeO3)2 were measured in the rotating frame as functions of temperature by 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) and 2H MAS NMR, respectively. There were no significant changes in T 1ρ for 1H and 2H nuclei near T C, except for a change in the number of proton signals. The transition is driven by the number of resonance lines resulting from the crystal’s ferroelastic properties. Near T m, the chemical shifts and T 1ρ values for 1H and 2H in the two materials changed abruptly, which implies variation of the structural geometry.