双原子分子晶体振动弛豫过程的分子动力学研究

MOLECULAR DYNAMICAL STUDY OF THE VIBRATIONAL RELAXATION PROCESS IN A DIATO MICMOLECULAR SOLID

用分子动力学方法研究瞬时加热振动自由度后的能量弛豫过程.晶元包含128个双原子分子,采用周期性边界条件和体心立方结构,对于分子内和分子间原子相互作用采用双莫尔斯势.发现平衡时间的对数与因子,f_21之间存在线性关系,而f_21正比于分子内振动与格波振动的频率比.

Energy relaxation processes initiated by suddenly heating of the vibrational degrees of freedom were studied with molecular dynamical method. A unit cell of bcc structure containing 128 diatomic molecules with periodic boundary conditions was considered. Compound Morse potential was assumed as the interactions of intra- and intermolecular atoms. It was found that the logarithm of equilibration time depends linearly upon a factor f31 which is proportional to the frequency ratio of the intra- and intermolecular vibrations.