Examination of the electronic structure of oxygen-containing PAH dimers and trimers
Examination of the electronic structure of oxygen-containing PAH dimers and trimers
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DOI：
10.1016/j.proci.2018.05.057
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发表时间：
2019
影响因子：
3.4
通讯作者：
Jennifer A. Giaccai;J. Houston Miller
中科院分区：
文献类型：
--
作者：
Jennifer A. Giaccai;J. Houston Miller
氧与多环芳烃（PAH）的相互作用既可以发生在火焰中，也可以发生在烟尘的大气氧化过程中。过去的实验测量PAH的烟尘样品收集后立即燃烧，从大气中，或在火焰中的PAH结构内的各种氧部分。本研究调查了含氧多环芳烃的电子结构，以深入了解它们与光的相互作用，以更好地解释光谱测量，并认识到含氧多环芳烃在大气辐射强迫中的作用。我们的研究表明，醚和羟基部分PAH上的氧显示HOMO-LUMO间隙（HLG）的变化不大，而酮和醛显示HLG减少0.5 eV。当PAH分子上存在一个以上的酮时，该效果增强，并且在随后的脱氢成醌样结构中进一步增强。在二聚体和三聚体中存在具有酮官能团的含氧PAH将显著降低PAH堆叠的HLG。这可能对大气煤烟与太阳辐射的相互作用产生重大影响。
Interactions of oxygen with polynuclear aromatic hydrocarbons (PAH) can occur both in the flame and during oxidation of soot atmospherically. Past experimental measurements of PAH in soot samples collected either immediately after combustion, from the atmosphere, or in a flame show a variety of oxygen moieties within the PAH structures. This study investigated the electronic structure of oxygen-containing PAH to gain insight into their interaction with light both to better interpret spectroscopic measurements and to recognize the role of oxygen-containing PAH in atmospheric radiative forcing. Our research has shown that oxygen in ethers and hydroxyl moieties on PAH showed little change to the HOMO-LUMO gap (HLG), whereas ketones and aldehydes show a HLG decrease of 0.5 eV. The effect is enhanced when more than one ketone is present on a PAH molecule and further enhanced in subsequent dehydrogenation to a quinone-like structure. The presence of an oxygen-containing PAH with a ketone functional group in a dimer and trimer will substantially lower the HLG of the PAH stack. This may have a significant effect in the interaction of atmospheric soot with solar radiation.