采用从头算程序对MgO表面 3种不同配位位置吸附Cl2 的构型进行优化 ,并用扩展休克尔紧束缚 (EHT)晶体轨道方法对MgO的缺陷和不规则表面吸附Cl2的可能构型进行能带计算 ,讨论了吸附前后能带组成和成键性质的变化。研究表明 :MgO表面吸附Cl2 将更趋向于吸附在O原子上而非Mg原子上 ,而且在 3种配位中MgO表面三配位氧最有利于吸附Cl2 ;吸附时 ,电子从O原子转移到Cl2 分子的反键轨道 ,但是各种吸附构型的MgO表面对Cl2 的吸附作用均比较微弱 ,是典型的物理吸附。 Adsorption of Cl2 on three different sites on the surface of MgO by ab initio procedure was optimized and the bandgap of MgO and the possible configuration of Cl2 on the surface of the MgO were optimized by the extended Hicker-Toll bond (EHT) The changes of the band composition and bonding properties before and after the adsorption were discussed. The results show that Cl2 adsorbed on MgO surface will tend to adsorb on O atoms instead of Mg atoms, and the three coordination oxygen of MgO surface is most favorable for Cl2 adsorption on the three kinds of coordination sites. At the time of adsorption, electrons are transferred from O atoms to Cl2 molecule antibonding orbital, but all kinds of adsorption configuration of MgO surface adsorption of Cl2 are relatively weak, is a typical physical adsorption.