An sp-hybridized all-carboatomic ring, cyclo[18]carbon: Electronic structure, electronic spectrum, and optical nonlinearity
An sp-hybridized all-carboatomic ring, cyclo[18]carbon: Electronic structure, electronic spectrum, and optical nonlinearity
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DOI：
10.1016/j.carbon.2020.05.023
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发表时间：
2020-09-15
期刊：
影响因子：
10.9
通讯作者：
Chen, Qinxue
中科院分区：
文献类型：
--
作者：
Liu, Zeyu;Lu, Tian;Chen, Qinxue
采用含时密度泛函理论计算方法研究了具有新型拓扑结构的sp杂化环[18]碳的电子光谱和光学非线性性质。分子轨道分析表明，环[18]碳的σ分子轨道的能级很低，两组相互垂直的高位π分子轨道的能级几乎相同。模拟的吸收光谱表明，环[18]碳在π → π ~* 跃迁时有两个可探测的吸收带：一个在219.4nm处的强吸收带和一个在191.4nm处的弱吸收带。通过理论分析，详细研究了最大吸收峰的振子强度。对分子响应性质的精确计算表明，环[18]碳由于其二维环状结构而具有明显的非线性各向异性。特别是环[18]碳显示出很大的二阶超极化率，并在非线性光学中表现出明显的光学色散。超极化率密度的进一步分析揭示了所研究的环[18]碳的巨大非线性光学性质的本质。(c)2020爱思唯尔有限公司保留所有权利。
The electronic spectrum and optical nonlinearity of the sp-hybridized cyclo[18]carbon with novel topology are studied by means of (time-dependent) density functional theory calculations. Molecular orbital analysis shows that the energy levels of sigma molecular orbitals of the cyclo[18]carbon are very low, and the energies of two sets of high-lying pi molecular orbitals, which are perpendicular with each other, are almost the same. The simulated absorption spectrum shows that the cyclo[18]carbon exhibits two detectable absorption bands corresponding to pi ->pi* transition: one strong absorption at 219.4 nm and one weak absorption at 191.4 nm. The considerable oscillator strength of the maximum absorption peak has detailedly investigated via theoretical analysis. Accurate calculation of molecular response properties shows that the cyclo[18]carbon has apparent nonlinear anisotropy due to its two-dimensional looping structure. In particular, the cyclo[18]carbon shows a great second-order hyperpolarizability and displays an obvious optical dispersion in optical nonlinearity. Further analysis of hyperpolarizability density reveals the nature of the great nonlinear optical properties of the studied cyclo[18]carbon. (c) 2020 Elsevier Ltd. All rights reserved.