Negative ion photoelectron spectra of ISO3-, IS2O3-, and IS2O4- intermediates formed in interfacial reactions of ozone and iodide/sulfite aqueous microdroplets
Negative ion photoelectron spectra of ISO3-, IS2O3-, and IS2O4- intermediates formed in interfacial reactions of ozone and iodide/sulfite aqueous microdroplets
复制标题
臭氧和碘化物/亚硫酸盐水溶液微滴的界面反应中形成的 ISO3-、IS2O3- 和 IS2O4- 中间体的负离子光电子能谱
DOI：
10.1063/1.4969076
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发表时间：
2016-12-21
影响因子：
4.4
通讯作者：
Wang, Xue-Bin
中科院分区：
文献类型：
--
作者：
Qin, Zhengbo;Hou, Gao-Lei;Wang, Xue-Bin
在臭氧与水中碘/硫氧化物微滴之间的反应中，检测到三种短暂的阴离子中间体，ISO_3~-，IS2O_3~-和IS2O_4~-。这些物种可能在臭氧驱动的无机气溶胶的形成中发挥重要作用；然而，它们的化学性质在很大程度上仍不清楚。这就是使用负离子光电子能谱(NIPES)和从头算模拟所解决的问题。NIPE谱表明，三种阴离子物种均具有较高的绝热脱附能(ADE)，对ISO_3~-、ISO_2O_3~-和IS2O_4~-分别为-4.62+/-0.10、4.52+/-0.10和4.60+/-0.10 eV。在基态跃迁特征中可以观察到具有S-O对称伸缩模频率的振动级数。密度泛函理论计算表明，存在几个涉及不同成键情形的低位异构体。基于CCSD(T)计算的进一步分析表明，最低的能量结构以I-S键和S-S键的形成为特征，对于isO_3-、isO_3-和is2O_4-，可将其结构视为与I、IS和ISO相连的SO_3。计算得到的ADE和垂直剥离能与实验结果符合得很好，进一步支持了所确定的最小能量结构。所获得的这些阴离子中间体和中性自由基的本征分子性质应该有助于理解它们在大气中的光化学反应。由AIP出版公司出版。
Three short-lived, anionic intermediates, ISO3-, IS2O3-, and IS2O4-, are detected during reactions between ozone and aqueous iodine/ sulfur oxide microdroplets. These species may play an important role in ozone-driven inorganic aerosol formation; however their chemical properties remain largely unknown. This is the issue addressed in this work using negative ion photoelectron spectroscopy (NIPES) and ab initio modeling. The NIPE spectra reveal that all of the three anionic species are characterized by high adiabatic detachment energies (ADEs) - 4.62 +/- 0.10, 4.52 +/- 0.10, and 4.60 +/- 0.10 eV for ISO3-, IS2O3-, and IS2O4-, respectively. Vibrational progressions with frequencies assigned to the S-O symmetric stretching modes are discernable in the ground state transition features. Density functional theory calculations show the presence of several low-lying isomers involving different bonding scenarios. Further analysis based on high level CCSD(T) calculations reveal that the lowest energy structures are characterized by the formation of I-S and S-S bonds and can be structurally viewed as SO3 linked with I, IS, and ISO for ISO3-, IS2O3-, and IS2O4-, respectively. The calculated ADEs and vertical detachment energies are in excellent agreement with the experimental results, further supporting the identified minimum energy structures. The obtained intrinsic molecular properties of these anionic intermediates and neutral radicals should be useful to help understand their photochemical reactions in the atmosphere. Published by AIP Publishing.