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核磁共振实验表明,LiKSO4在Tc=195K发生结构相变。本文报道了温度低于Tc时,Li位电场梯度张量的温度依赖关系。结合理想离子晶体模型,讨论了该晶体的结构,指出室温相Li的位置并不像Bradley所推测的,在(2/3,1/3,0.849)的位置,而应在(2/3,1/3,0.706)的位置;195K的相变是由于Li离子的位移造成;低温相的空间群可能为R3。A structural phase transition in crystal LiKSO4 at Tc = 195 K was confirmed by NMR experiment previously. In this article, the temperature dependence of the electric field gradient tensor at lithium site in the range of 110-300 K is reported, and combined with a simplified ion crystal model the crystal structure is discussed. It is shown that even in the room temperature phase, the lithium position should be at (2/3, 1/3, 0.706) instead of the position at (2/3, 1/3, 0.849) suggested previously by Bradley. The phase transition is attributed to the displacement of lithium ions. The space group of the low temperature phase may be R3.
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