基于密度泛函理论和含时密度泛函理论下富勒烯B24N24光谱性质研究

本文在B3LYP/6-31g(d)基组水平上, 利用密度泛函理论(DFT)优化了B24N24团簇的几何和电子结构. 研究结果表明, 优化所得B24N24团簇的几何结构对称性分别为S4、C2、S8和O；在基态稳定结构基础上, 得出其输运性质, 既非p型输运材料, 亦非n型输运材料, 即不具有输运性质；在优化好的基态结构基础上, 又研究了它的红外和拉曼分子振动谱, 四种团簇的红外-拉曼振动谱的振动强度排序均为O>S8>S4>C2；随后采用含时密度泛函理论(TDDFT)，同样在B3LYP/6-31g(d)基组水平上, 计算了这四种物质在CH2Cl2溶剂中的UV-Vis吸收谱特性, 研究表明跃迁能级数量越多,吸收谱振动强度越强， 并且这些分子的紫外-可见吸收谱的振动强度排序为S4>C2>S8>O.

DFT and TDDFT study on spectra of B24N24 fullerene

The geometrical and electronic structure of B24N24 are optimized by using density functional theory (B3LYP) at the 6-31g(d) level. The results show that the geometrical structure symmetries of the optimized B24N24 clusters are S4, C2, S8, O. Based on the stable structure of the ground state, it is concluded that its transport properties are neither the p-type transport material, nor the n-type transport material, so, they have no transport properties. On the basis of the optimized ground state structure, the IR-Raman spectra of the four clusters were obtained. and the order of vibrational intensity for the IR-Raman spectra of the four clusters was O>S8>S4>C2. The Time-dependent density functional theory (TDDFT) was also used at the B3LYP/6 -31 g (d) level, the UV-Vis absorption spectra of these four compounds in CH2Cl2 were calculated, the results show that the more transition energy levels, the stronger the vibration intensity of the absorption spectrum. The vibrational intensities of the UV-Vis absorption spectra of these molecules were sorted as S4>C2>S8>O.