Weisman J L, Lee T J, Head-Gordon M
Department of Chemistry, University of California, Berkeley, and Lawrence Berkeley National Laboratory, 94720, USA.
Spectrochim Acta A Mol Biomol Spectrosc. 2001 Mar 15;57(4):931-45. doi: 10.1016/s1386-1425(00)00454-6.
Due to their stability, closed shell polycyclic aromatic hydrocarbon (PAH) cations are possible candidates as carriers for some of the diffuse interstellar bands (DIBs). The electronic absorption spectra and ionization potentials of several closed shell PAH cations are determined in this study. We use density functional theory (DFT) at the BLYP/6-31G* level to determine the ionization potentials and thus confirm the stability of the PAH cations of interest. We use time-dependent density functional theory (TDDFT), again at the BLYP/6-31G* level, to calculate the vertical excitation energies and oscillator strengths of the PAH cations. We observe dominant single absorptions within the DIB spectral region of interest in all of the PAH cation spectra except for the smallest member of the series.
由于其稳定性，闭壳多环芳烃（PAH）阳离子有可能成为某些弥漫星际带（DIB）的载体候选物。本研究测定了几种闭壳PAH阳离子的电子吸收光谱和电离势。我们使用BLYP/6-31G水平的密度泛函理论（DFT）来确定电离势，从而确认所关注的PAH阳离子的稳定性。我们再次使用BLYP/6-31G水平的含时密度泛函理论（TDDFT）来计算PAH阳离子的垂直激发能和振子强度。我们观察到，除了该系列中最小的成员外，所有PAH阳离子光谱在感兴趣的DIB光谱区域内都有主要的单吸收峰。
