氧分子O_4的结构与性能的密度泛函理论研究

Density functiona theory study on the structure and properties of O_4 molecule

采用密度泛函理论(DFT)中的B3LYP方法,在LANL2DZ基组水平上对O_n^(0,±)(n=2～4)分子的各种可能构型进行了几何结构优化,预测了它们的基态构型,并对O_4^(0,±)分子基态结构的能量、振动光谱和芳香特性进行了理论研究。结果表明:O_4分子的基态结构为对称性为D_(2d)的非平面的四边形,阴阳离子的基态结构都为对称性为D_(4h)的平面正四边形;O_4具有芳香性,O_4和O_4^+具有反芳香性;O_4^(0,±)分子的基态结构均具有红外活性和拉曼活性;红外光谱均出现1个较强的振动峰,拉曼光谱中O_4、O_4^+、O_4^-分别有4个、3个和1个较强的振动峰。

All the possible geometrical structures of O_n^（0,±）（n=2～4） molecules are optimized with a hybrid density functional theory（B3LYP）at LANL2DZ level,the ground state structures are decided as well.In addition,the energy,vibrational spectra and aromaticity of O_4^（0,±） molecules are studied.It is shown that the ground state structures of O_4 molecule is a nonplanar tetragon of D_（2d） symmetry,while the ground state structures of O_4~＋ and O_4^- molecule are all planar tetragon of D_（4h） symmetry.Aromaticity is found in the O_4^-,while antiaromaticity is found in the O_4 and O_4~＋.The ground-state structures of the O_4^（0,±） molecule are all infrared activity and Raman activity,the O_4^（0,±） molecule have all one strong vibration peak in the infrared spectra.In the Raman spectra,there are four,three and one strong vibration peaks of molecule O_4,O_4~＋ and O_4^- molecule respectively.