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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 .
The ab initio method was used to simulate the color centers and the self-trapping excitons (STEs) in the ion crystal of KMgF3.The geometries of quantum clusters containing F-centers were optimized and the F-centers were calculated at 1s ground state and 2p excitation State Mulliken charge distribution.The simulation results show that the lattice relaxation around the F-core is small, the F-electron at the ground state is in the anion vacancy and the F-wave at the excited state is relatively expanded. The results show that the VK center moves toward the adjacent gap but keeps the molecular axis parallel to the [110] crystal. The relaxation of the self-excited exciton is a superposition of the axial translation and the rotation of the molecule. The calculated F- The optical excitation energy of VK and the luminescence of STE coincide well with the experiment.