Linear and nonlinear feature of electronic excitation energy in carbon chains HC2n+1H and HC2nH
Linear and nonlinear feature of electronic excitation energy in carbon chains HC2n+1H and HC2nH
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DOI：
10.1002/qua.20023
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发表时间：
2004-06
影响因子：
2.2
通讯作者：
Congjie Zhang;Z. Cao;Hai-Shun Wu;Qianer Zhang
中科院分区：
文献类型：
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作者：
Congjie Zhang;Z. Cao;Hai-Shun Wu;Qianer Zhang
用密度泛函理论研究了HC 2nH（n = 1-13）和HC 2n +1H（n = 2-12）分子的几何构型、成键和振动频率.用含时密度泛函理论和从头算二阶多组态微扰方法分别计算了HC 2 n H（n = 1-5）的X 1 <$+ g → 1 1 <$+ u跃迁和HC 2 n + 1 H（n = 2-5）的X 3 <$- g → 1 3 <$- u跃迁的垂直激发能.在此基础上，给出了线性多炔化合物HC 2n +1H和HC 2n +1H的激发能随分子尺寸变化的解析表达式.这种分析的A-n关系与实验观测结果吻合得很好.理论研究表明，HC 2 n + 1 H和HC 2 n H基态和激发态的成键相似性和差异性决定了多炔化合物的线性和非线性光谱特征.
Density functional theory has been used to investigate the geometries, bonding, and vibrational frequencies of HC 2 n H (n = 1-13) and HC 2 n + 1 H (n = 2-12). Vertical excitation energies for the X 1 Σ + g → 1 1 Σ + u transition of HC 2 n H (n = 1-5) and for the X 3 Σ - g → 1 3 Σ - u transition of HC 2 n + 1 H (n = 2-5) have been calculated by the time-dependent density functional theory and ab initio second-order multiconfiguration perturbation method, respectively. On the basis of the present calculations, explicit expressions for the size dependence of excitation energy in linear polyynes HC 2 n + 1 H and HC 2 n + 1 H are suggested. Such analytical A - n relationships show good agreement with experimental observations. Theoretical investigations of relevant excited states demonstrate that distinct linear and nonlinear spectroscopic features in such polyynes can be ascribed to similarity and difference in bonding between the ground and excited states in HC 2 n + 1 H and HC 2 n H.