Autodetachment over Broad Photon Energy Ranges in the Anion Photoelectron Spectra of [O 2 – M ] − ( M = Glyoxal, Methylglyoxal, or Biacetyl) Complex Anions
Autodetachment over Broad Photon Energy Ranges in the Anion Photoelectron Spectra of [O 2 – M ] − ( M = Glyoxal, Methylglyoxal, or Biacetyl) Complex Anions
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[O 2 → M ] →（M = 乙二醛、甲基乙二醛或联乙酰）复合阴离子的阴离子光电子谱中宽光子能量范围内的自分离
DOI：
10.1021/acs.jpca.1c07163
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Jarrold, Caroline Chick
中科院分区：
文献类型：
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作者：
Dobulis, Marissa A.;McGee, Conor J.;Sommerfeld, Thomas;Jarrold, Caroline Chick
阴离子-中性对的复合物在星际介质、大气和生物系统等的化学和物理过程中普遍存在。然而，双分子阴离子物种，不能被描述为简单的离子-分子复合物，由于他们的竞争性电子亲和力受到较少的关注。在这项研究中，[O2-M]−（M=乙二醛，甲基乙二醛，或双乙酰）阴离子的光电子能谱得到了几个不同的光子能量的报告和解释的上下文中ofab initiocalculations。光谱不类似于光电子光谱ofM-或O2-“溶剂化”的中性伙伴。相反，所有的光谱主要是由近阈值自动脱离什么是可能的瞬态偶极束缚态的thecisconformers的复杂阴离子。中性的M·O2范德华簇和部分共价键合的络合阴离子之间非常低的Franck-Condon重叠导致在光谱中观察到低强度，宽的直接脱离。在2.88和3.495 eV光子能量下测得的[O2-乙二醛]−光谱还显示出在电子动能为0.5 eV时的特征，这更难以解释，尽管可能涉及阴离子的许多准束缚态。总的来说，这些特征指出了将络合阴离子描述为简单的离子-分子络合物的不足。
Complexes of anion–neutral pairs are prevalent in chemical and physical processes in the interstellar medium, the atmosphere, and biological systems, among others. However, bimolecular anionic species that cannot be described as simple ion–molecule complexes due to their competitive electron affinities have received less attention. In this study, the [O2–M]−(M= glyoxal, methylglyoxal, or biacetyl) anion photoelectron spectra obtained with several different photon energies are reported and interpreted in the context ofab initiocalculations. The spectra do not resemble the photoelectron spectra ofM–or O2–“solvated” by a neutral partner. Rather, all spectra are dominated by near-threshold autodetachment from what are likely transient dipole bound states of thecisconformers of the complex anions. Very low Franck–Condon overlap between the neutralM·O2van der Waals clusters and the partial covalently bound complex anions results in low-intensity, broad direct detachment observed in the spectra. The [O2-glyoxal]−spectra measured with 2.88 and 3.495 eV photon energies additionally exhibit features at ∼0.5 eV electron kinetic energy, which is more difficult to explain, though there are numerous quasibound states of the anion that may be involved. Overall, these features point to the inadequacy of describing the complex anions as simple ion–molecule complexes.