分子激光冷却是实验上产生冷分子的最重要进展之一。要找到适合做激光冷却实验的候选分子，就需要了解这些分子的结构参数和光谱数据，这些参数是选择分子的重要依据。详细计算了分子的X 态和A 态振动能级跃迁的Franck-Condon 因子以及转动超精细能级结构，考虑到分子的核自旋、激发态寿命、跃迁能级波长、暗态等参数，提出了一种新的适合进行激光冷却的候选分子（氟化镁），选择适当的能级跃迁来构建一个准闭合的能级系统。这些参数为光谱数据的实验测量提供了理论依据，为进一步的激光冷却实验奠定了基础。

Laser cooling of molecule is one of the most important progresses on the generation of cold molecules in experiments. To find a suitable candidate for laser cooling experiment, the molecular structure parameters and spectral data must be understood. These parameters are important basis of choosing molecules. The detailed calculations of vibronic structure and rotational hyperfine structure of the molecular X and A states are carried out. Considering the parameters of nuclear spins, excited lifetime, dark state,transition levels, and so on, a new suitable molecule (magnesium fluoride) for laser cooling is proposed, and the appropriate transition is used to form the quasi- closed energy level system for laser cooling. These parameters provide theory basis for the experimental measurement of spectral data, and lay a foundation for further laser cooling experiments.