Nuclear spin resonance study of the ion mobility in a KHSeO4 crystal

The ion mobility in a crystal of partially deuterated potassium hydroselenate (KHSe) was studied using nuclear spin resonance (NSR) of ¹H, ²H, ⁷⁷Se, and ³⁹K in a wide temperature range. The temperature dependences of the deuterium NSR spectra above 360 K exhibit changes in the line shape characteristic of chemical exchange processes. These exchange processes were studied in detail using two-dimensional ²H NSR spectroscopy. It was ascertained that the exchange between deuterons of hydrogen bonds take place in the entire temperature range under study. However, the measured conductivity was approximately one-hundredfold lower than that estimated from the exchange frequencies. It was assumed that the low conductivity in the temperature range under study is caused by closed dimers of SeO₄ groups in the KHSe structure.