KMgF_3晶体的色心和自陷态激子研究  

The colour centers and self-trapped exciton in KMgF_3

作　　者：黄桂芹[1] 刘楣[2] 陈凌孚[1] 

机构地区：[1]南京师范大学物理系,南京210097 [2]东南大学物理系,南京210096

出　　处：《物理学报》2005年第4期1702-1706,共5页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :10 1740 11);江苏省自然科学基金 (批准号 :BK2 0 0 10 0 2 )资助的课题~~

摘　　要：应用从头计算方法对KMgF3离子晶体中的色心和自陷态激子 (STE)进行了模拟研究 .对包含F心的量子团簇进行几何结构优化 ,并计算了F心处于 1s基态和 2p激发态的Mulliken电荷分布 .模拟结果表明 ,F心周围的晶格弛豫较小 ,处于基态的F心电子主要局域在阴离子空位处 ,而处于激发态的F心电子波函数则比较扩展 .计算结果表明 ,VK 心移向邻近的间隙位置 ,但仍保持分子轴向与 [110 ]晶向平行 .自陷态激子的弛豫是分子轴向平移与转动的叠加 .计算得到的F心、VK 心的光学激发能及STE的发光能与实验符合得较好 .ab initio method is used to model the colour centers and self-trapped excitons in KMgF3. The geometry optimization of the defect cluster, including the F center, shows that the relaxation of the lattice around the F center is very small. The calculated Mulliken populations for F center in its ground state and excite state show that the ground state wavefunction of F center is well localized, but the excited state wavefunction of it is more diffuse. Furthermore, our results show that the V-K center moves toward the nearby interstitial site, but keeping the molecular axis along the [110] direction. The relaxation of the selftrapped excitons consists of an axial translation superimposed with a rotation. The calculated excitation energies of F center, VK center and the emission energy of self-trapped exciton are compared with their experimental values.

关 键 词：KMgF3晶体 色心 自陷态激子 量子团簇 几何结构优化 

分 类 号：O74[理学—晶体学]