Yang Guochun, Guan Wei, Yan Likai, Su Zhongmin, Xu Lin, Wang En-Bo
Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, People's Republic of China.
J Phys Chem B. 2006 Nov 23;110(46):23092-8. doi: 10.1021/jp062820p.
Electronic spectrum of organoimide derivatives of hexamolybdates have first been calculated within the time-dependent density-functional theory in conjunction with Van Leeuwen-Baerends (LB94) exchange correlation potential, statistical average of orbital potentials (SAOP), and gradient-regulated connection potential (GRAC), respectively. The GRAC yields much better agreement with experiments for the excitation energies comparing with both LB94 and SAOP. The analysis of transition nature indicates that there is a significant difference between the diagonal and the orthogonal substituted derivatives. The static and dynamic third-order polarizabilities are calculated using time-dependent density-functional theory combined with the sum-over-states method. The results show that these derivatives possess remarkable large molecular third-order polarizabilities, especially for system 8 with -17882.6 x 10(-36) esu. This value is about 250 times that for the C(60) molecule. Adding the organoimide segment to the Mo(6)O(19) can substantially increase the nu value. This variation can be traced to the different electronic transition characteristics between the derivatives of Mo(6)O(19) and Mo(6)O(19). For our studied systems, increasing the conjugation length and diagonal substituted are efficient ways to enhance the third-order polarizability. Thus, the organoimide derivatives of hexamolybdates may comprise a new promising class of nonlinear optical materials from the standpoint of large values, small dispersion behavior, and high transparency.
首次分别在含时密度泛函理论结合范·李文-贝伦兹（LB94）交换关联势、轨道势统计平均值（SAOP）以及梯度调节连接势（GRAC）的条件下，计算了六钼酸盐有机酰亚胺衍生物的电子光谱。与LB94和SAOP相比，GRAC在激发能方面与实验结果的吻合度更高。对跃迁性质的分析表明，对角取代衍生物和正交取代衍生物之间存在显著差异。采用含时密度泛函理论结合态叠加法计算了静态和动态三阶极化率。结果表明，这些衍生物具有显著的大分子三阶极化率，特别是对于体系8，其值为-17882.6×10⁻³⁶ esu。该值约为C₆₀分子的250倍。在[Mo₆O₁₉]²⁻中添加有机酰亚胺片段可大幅提高nu值。这种变化可归因于[Mo₆O₁₉]²⁻衍生物和[Mo₆O₁₉]²⁻之间不同的电子跃迁特性。对于我们研究的体系，增加共轭长度和对角取代是提高三阶极化率的有效方法。因此，从具有大值、小色散行为和高透明度的角度来看，六钼酸盐有机酰亚胺衍生物可能构成一类新的有前景的非线性光学材料。
