氢氧化钠的高压拉曼散射研究

Raman scattering studies of sodium hydroxide under high pressure

采用金刚石对顶砧装置,利用原位高压拉曼散射技术对氢氧化钠(NaOH)进行了系统的高压实验研究.实验所达到的最高压力约为40 GPa,测量的波数范围为55~4000 cm^-1.在压力研究的范围内,NaOH于0.9 GPa时发生了一次结构相变,为正交晶体结构(α)到NiAs结构(γ)的转变.压力继续升高至最高压力约40 GPa范围内,再无相变发生.利用MS中的CESTEP模块对NaOH常压相和高压相的拉曼光谱进行了理论计算,并对两种结构的振动模式进行了指认.

The NaOH had been studied at high pressure by in-situ Raman scattering measurement using a diamond anvil cell at room temperature.The experiment had been conducted up to 40 GPa.The spectra were measured ranged from 55 to 4000 cm^-1.The spectroscopic analyses revealed that one phase transition occurred at 0.9 GPa,which was a transformation from orthogonal crystal structure(α)to NiAs structure(γ).No phase transition occurred at the pressure continuing rise to the maximum pressure about 40 GPa.The Raman spectra of NaOH at ambient conditions and high-pressure conditions were calculated and the vibration modes of the two structures were assigned by using the CASTEP code in MS.