碱金属卤化物键长、德拜温度和热膨胀系数的温度效应

以碱金属卤化物为研究对象，根据局域键平均近似方法，从热膨胀系数的定义出发，建立热膨胀系数和键长的温度效应函数表达式。定量获取碱金属卤化物的键长、刚性因子、德拜温度和热膨胀系数。结果表明：①碱金属卤化物的热膨胀系数与结合能成反比；②同类碱金属卤化物中，从氟碱化物到碘碱化物德拜温度逐渐减小而热膨胀系数逐渐增大；③碱金属卤化物的键长在其德拜温度的三分之一处，由非线性转变为线性热伸长。

Temperature Dependence of Bond Length,Debye Temperature and Thermal Expansion Coefficient of Alkali Halides

Temperature dependence functional expressions of bond length and thermal expansion coefficient of alkali halides without empirical parameters were established with local bond average approach and definition of thermal expansion coefficient. We obtained quantitatively the bond length, rigidity factor, Debye temperature and thermal expansion coefficient of alkali halides. It was found that: ① The thermal expansion coefficient of alkali halides is inversely proportional to the cohesive energy; ② The Debye temperature decreases and the thermal expansion coefficient increases gradually from alkali fluorides to alkali iodides in the same kind of alkali halides; ③ The bond length of alkali halides changes from nonlinear to linear thermal elongation at one third of its Debye temperature.