用从头计算分子轨道法和密度泛函理论 ,在HF/6 31G 和B3LYP/6 31G 水平上对ClnAlNHn 和HnAlNHn(n =1～ 3)及其碎片分子的几何构型、电子结构、振动光谱和化学热力学性质进行了理论研究。结果表明 ,优化几何参数与实验值相吻合。Cl2 AlNH2 和H2 AlNH2 分子中 ,Al-N键为由一个σ键和一个π键组成的双重键 ,旋转势垒分别为 34.10和 5 4 .35kJ·mol- 1。而Cl3AlNH3和H3AlNH3分子中 ,Al-N键为σ型单键 ,对应的旋转势垒为 0 .31和 2 .5 0kJ·mol- 1,有较小的势垒 ,易于旋转。化学热力学计算表明 ,ClnAlNHn 和HnAlNHn 分子中 ,Al-N键能的大小顺序为△Hn =2>△Hn =1>△Hn =3. The geometries, electronic structures and vibrational spectra of ClnAlNHn and HnAlNHn (n = 1 ~ 3) and their fragment molecules at HF ​​/ 6 31G and B3LYP / 6 31G were calculated by ab initio molecular orbital method and density functional theory Chemical thermodynamic properties of a theoretical study. The results show that the optimized geometric parameters are consistent with the experimental values. In the Cl2 AlNH2 and H2AlNH2 molecules, the Al-N bond is a double bond consisting of a σ bond and a π bond with a rotational barrier of 34.10 and 5.4 kJ · mol-1, respectively. In the Cl3AlNH3 and H3AlNH3 molecules, the Al-N bond is a sigma-type single bond, corresponding to the rotation barrier of 0.31 and 2.5 0 kJ · mol-1, which has a smaller potential barrier and is easy to rotate. Chemical thermodynamic calculations show that the order of the Al-N bond energies in ClnAlNHn and HnAlNHn molecules is ΔHn = 2> ΔHn = 1> ΔHn = 3.