基于光学材料中锂元素的含量对物质稳定性及光学性质的影响, 利用Gaussian 03程序包, 采用密度泛函理论中的B3LYP方法, 在6-31G(d)水平上对光学材料LinC(n=1~9)团簇进行了结构稳定性及振动光谱的研究.结果表明: 当n>3时团簇的结构为三维立体结构, 碳原子被俘获在锂原子笼内.除了Li2C外, 其它团簇的体系基态都处于低电子态, 当n为偶数时为单重态, n为奇数时为双重态.在团簇稳定性上, 明显的奇偶振荡效应出现在能量的二阶差分和最高占据轨道与最低空轨道的能隙中.对于LinC, n为偶数的团簇比相邻的奇数团簇更稳定.碎片能量分析表明最有可能的团簇生长路径是在Lin-1C团簇上结合一个锂原子成为LinC团簇.LinC团簇的光谱落在指纹区域.随着锂原子数的增加, 振动频率减小.当锂原子数为偶数时, 基态结构的频率差是最小的, 当锂原子数为奇数时, 基态结构的频率差却是最大的.

Based on the influence of lithium content in some optical materials to the structure stability and optical proterties,the structure stablility and vibration spectroscopy of carbon-doped clusters LinC(n=1~9) were investigated with density functional theory at the B3LYP/6-31G(d) level.The computed results shown that the structure were three dimension(n>3) structure for LinC except for Li2C and the carbon atom was seen to be trapped in a Li cage.Especially,the electron ground state was found to be a low state for LinC cluster,singlet for n is even while doublet for n is odd.A strong even-odd alternation in the cluster stability appeared in the incremental binding energy,with their n-even numbers being much more stable than the adjacent odd-numbered ones.These parity effects also appeared in the second difference in energy and the gap between HOMO-LUMO.In addition,the dominant channel was losing a Li particle for LinC clusters by analyzing the fragmentation energies.The spectroscopy range of LinC clusters located in fingering area.The vibration frequency of LinC clusters decreased with the increasing of the numbers of Lithium atoms.Moreover,the difference between the lowest and the highest vibration frequency shown maxmium as the number of lithium atoms was odd while it shown minimum as the number of lithium atoms was even.