The spin-lattice relaxation time, T1, and the spin-spin relaxation time, T2, of the 1H,

2H and 39K nuclei in KHSeO4 and KDSeO4 crystals were determined at 160 to

420K. The T1 of the 39K nuclei in the two crystals were found to decrease with

increasing temperature, and the spin-lattice relaxation rate, T1

-1, for 39K was

proportional to Tk. In the case of KHSeO4, T1

-1 for the 39K nuclei was found to have

a very strong temperature dependence, i.e. it was proportional to T7. The

temperature dependence of the 39K relaxation rate in KDSeO4 was in accordance

with a Raman process, as T1

-1 was proportional to T2. Thus, for the 39K nuclei in

the two crystals, Raman processes with k = 2 and 7 were due to the coupling of

electric quadrupole moments to the thermal fluctuations of the local electric field

gradients.

A Study of the Electric Quadrupole Raman Processes of the Proton-Conducting

KHSeO4 and KDSeO4 Single Crystals Using 1H, 2H and 39K NMR. A.R.Lim,

C.S.Yoon: Physica Status Solidi B, 2008, 245[8], 1641-6