C_(50)富勒烯及其二聚物C_(100)、C_(101)的光学性质

Optical Properties of C_(50) Fullerene and Its Two Dimers C_(100) and C_(101)

运用B3LYP方法在6-31G^＊基组水平上对C50富勒烯以及它的两个不同二聚物C100,C101的几何构型进行了全优化．在优化所得构型的基础上，采用TDB3LYP方法在3-21G^＊基组水平上对其激发态性质、电子吸收光谱进行了研究，根据计算得到的态态间跃迁偶极矩和跃迁能等数据，结合使用态求和公式进一步计算得到了它们不同光学过程中的三阶非线性极化率．结果表明，当C50富勒烯二聚以后，其电子吸收光谱的最大波长吸收蜂发生了明显的红移，三阶非线性极化率有了较大的提高．其中，【5，5】-【5，5】哑铃型二聚物C101有着比【2＋2】闭环型二聚物C100更大的三阶非线性极化率．

Configurations of C50 fullerene and its two dimers C100 and C101 were optimized at B3LYP/6-31G^＊ level. On the basis of the optimized geometrical structures, their excited states, electronic absorption spectra and third-order nonlinear optical polarizabilities in different optical processes were investigated at TDB3LYP/3-21G^＊ level coupled with sum-over-states method. The results obtained from the electronic absorption spectra showed that the largest wavelength absorption peaks of C50 fullerene dimers had a remarkable red shift compared with that of C50 fullerene, and their third-order nonlinear optical polarizabilities increased after the dimerization. Especially, [5,5]-[5,5] dumbbell-like C50 fullerene dimer C101 had a larger third-order nonlinear optical polarizability than [2＋2]-closed C50 fullerene dimer C100.