Ab Initio Study of Polycyclic Aromatic Hydrocarbons in Their Ground and Excited States
Ab Initio Study of Polycyclic Aromatic Hydrocarbons in Their Ground and Excited States
复制标题
多环芳烃基态和激发态的从头算研究
DOI：
10.1021/jp980467k
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发表时间：
1998
影响因子：
2.9
通讯作者：
V. McGuffin
中科院分区：
文献类型：
--
作者：
J. Goodpaster;J. F. Harrison;V. McGuffin
本文报道了四种多环芳烃（PAHs）：芘、苯并（a）芘、荧蒽和苯并（B）荧蒽的基态和激发态从头计算结果。基态的几何形状，红外频率，激发能量，激发态电子分布，激发态的几何形状，激发态的频率的变化进行计算和定量比较实验数据。与实验的总体一致性是相当好的，最大的差异发生在预测分子的激发能。电子密度的变化与激发态几何形状的变化相关，所有的多环芳烃在激发时都沿其极化轴沿着延长。这些计算也被用来检查交替（芘和苯并（a）芘）和非交替（荧蒽和苯并（B）荧蒽）多环芳烃之间的特征差异。相对于交替异构体，非交替异构体往往具有更高的基态能量，更低的相对分子质量。
Both ground- and excited-state ab initio calculations are reported for four polycyclic aromatic hydrocarbons (PAHs): pyrene, benzo(a)pyrene, fluoranthene, and benzo(b)fluoranthene. Ground-state geometries, IR frequencies, excitation energies, changes in excited-state electron distributions, excited-state geometries, and excited-state frequencies are calculated and quantitatively compared to experimental data. Overall agreement with experiment is quite good, with the largest discrepancies occurring when predicting the excitation energies of the molecules. Changes in electron density correlate with changes in the excited-state geometry, with all PAHs lengthening along their axis of polarization upon excitation. These calculations are also used to examine characteristic differences between the alternant (pyrene and benzo(a)pyrene) and nonalternant (fluoranthene and benzo(b)fluoranthene) PAHs. Relative to their alternant isomers, nonalternant PAHs tend to possess higher ground-state energies, lower relative ...