The ferroelectric phase transition at T(C2) (=370K) in RbHSeO(4) has been studied by (1)H and (87)Rb solid-state NMR. Although not large, the spin-lattice relaxation time, T(1), and the spin-spin relaxation time, T(2), of rubidium and of the alpha- and beta-type protons show distinct change near the phase transition. The intensity of the signal due to the alpha-type protons decreases with increasing temperature, and the intensity of alpha-type protons is quite weak above 330K: at a temperature which is about 40K lower than the phase transition temperature, the ordering of the alpha-type protons occurs. The alpha-type protons in the ferroelectric phase lead to a noticeable change in the proton magnetic resonance spectra. Our study of the (1)H spectra shows that the ferroelectric phase transition in RbHSeO(4) is of order-disorder type and is due to the ordering of protons in hydrogen bonds.

中文翻译：

---

（1）H和（87）Rb核磁共振研究RbHSeO（4）单晶的有序无序相变。

通过（1）H和（87）Rb固态NMR研究了RbHSeO（4）中T（C2）（= 370K）处的铁电相变。尽管不大，但of和α型和β型质子的自旋晶格弛豫时间T（1）和自旋自旋弛豫时间T（2）在相变附近显示出明显的变化。由于温度升高，由α型质子引起的信号强度降低，并且在330K以上时，α型质子的强度非常弱：在比相变温度低约40K的温度下，α的有序性型质子发生。铁电相中的α型质子导致质子磁共振光谱发生明显变化。