Density functional studies of the luminescence of Si29H36
Density functional studies of the luminescence of Si29H36
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Si29H36 发光的密度泛函研究
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
D. Sundholm
中科院分区：
文献类型：
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作者：
D. Sundholm
采用含时微扰理论（TDDFT）方法，在密度泛函理论（DFT）水平上对Si_（29）H_（36）团簇的基态和最低激发态的分子结构进行了优化.在TDDFT水平上计算了完全优化的分子结构的电子吸收能和发射能。发现使用Becke-Perdew（BP）泛函为激发态的平衡结构计算的激发能比基态结构的垂直激发能小0.72 eV。计算出的发射光的波长为396 nm，这与实验结果吻合得很好，因为硅团簇发射蓝光。由激发态弛豫引起的小的结构变化在基态结构中引入应变。应变和松弛被发现同样有助于发射光的大的红移。因此，目前的计算不支持的概念，激发态的势能面有一个双阱结构。
The molecular structures of the ground and the lowest excited state of a Si29H36 cluster have been optimized at the density-functional-theory (DFT) level using the time-dependent perturbation-theory (TDDFT) approach for the excited state. The electronic absorption and emission energies for the fully optimized molecular structures have been calculated at the TDDFT level. The excitation energy calculated for the equilibrium structure of the excited state using the Becke–Perdew (BP) functional was found to be 0.72 eV smaller than the vertical excitation energy for the ground-state structure. The calculated wavelength of the emitted light is 396 nm which agrees well with experiment as the silicon cluster emits blue light. Small structural changes caused by the relaxation of the excited state introduce strains in the ground-state structure. The strain and the relaxation are found to contribute equally to the large red shift of the emitted light. Thus, the present calculations do not support the notion that the potential-energy surface of the excited state has a double-well structure.