本文以分子质心平移、转动权重坐标和分子内正则坐标为基组给出非刚性分子晶体振动动力学的对称性质,得到一种等价的波矢群多重可约表示以及晶体正则模对称分类公式,从而使相应的动力学方程对角方块化.最后给出波矢为 ((2πμ)/α)k 时,立方晶系四腈乙烯的对称性应用例子. In this paper, the symmetry properties of the vibrational dynamics of non-rigid molecular crystals are given based on the translation of molecular centers of mass, the rotational weighting coordinates and the intramolecular canonical coordinates. An equivalent wave-vector multi-contractible representation and symmetric classification of crystal regular modes are obtained , So that the corresponding kinetic equation diagonal square block.Finally, the wave vector of ((2πμ) / α) k, the tetragonal tetramene ethylene symmetry application example.