Ca_2P_2O_7温致相变的拉曼光谱研究

Temperature Dependent Raman Spectra and PhaseTransformation Study of Ca_2P_2O_7

本文采用高温原位拉曼光谱研究了冷却方式对焦磷酸钙相变及其晶型制备的影响,并结合第一性原理计算,解析了α与β焦磷酸钙晶体的拉曼振动归属。研究表明,从相变点之上快冷至室温可得到α焦磷酸钙;当焦磷酸钙在1373K保温时发生相变,并进一步缓冷得到β焦磷酸钙;而当在1373K保温快冷可得到α与β的混合相,混合相中各组分含量由相变点保温时间和冷却速率有关。高温原位拉曼光谱能原位观察无机材料制备过程中相的变化。

In situ high temperature Raman spectroscopic technique was applied to investigate preparation of the different phase crystals of and the transformation affected by thermal processing.Vibrational modes of both α-Ca2P2O7（high temperature phase） and β-Ca2P2O7（low temperature phase） crystals were assigned by the aid of the first principle calculation.It reveals that α-Ca2P2O7 crystal at ambient temperature can be obtained by being fast cooled from above the phase transition point while β-Ca2P2O7 crystal being prepared after being maintained at 1373 K for considerable duration time and being slowly cooled.Otherwise,a mixture of α and β-Ca2P2O7 crystals can be evolved without considerable thermal processing.It also demonstrates that in situ high temperature Raman spectroscopic technique is a unique probe to investigate the process of inorganic materials preparations.