Dipole effects in the photoelectron angular distributions of the sulfur monoxide anion
Dipole effects in the photoelectron angular distributions of the sulfur monoxide anion
复制标题
一氧化硫阴离子光电子角分布的偶极效应
DOI：
10.1039/d2cp03337b
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发表时间：
2022
影响因子：
3.3
通讯作者：
Sanov, Andrei
中科院分区：
文献类型：
--
作者：
Ru, Beverly;Hart, C. Annie;Mabbs, Richard;Gozem, Samer;Krylov, Anna I.;Sanov, Andrei
利用光电子成像光谱研究了线偏光355nm （3.49 eV）、532 nm （2.33 eV）和611 nm （2.03 eV）下SO−光剥离的光电子角分布（PADs）。在532和611 nm处的测量得到了SO的X3Σ -和a1Δ电子态，而在3555 nm处的测量也得到了b1Σ+电子态。总的来说，光电子各向异性参数值遵循π*-轨道光剥离时电子动能（eKE）的一般趋势。这一趋势与O2−相似，但SO−曲线的最小值向更小的eKE偏移。这种转移主要归因于离开电子与中性硫核偶极矩的出口通道相互作用，而不是SO -和O2 -分子轨道的不同形状。在考虑的几个从头算模型中，有两种方法与实验结果非常吻合：一种方法将离开的电子表示为点偶极场哈密顿函数的本征函数的叠加，另一种方法描述了从两个分离的电荷中心发出的库仑波，其中硫带部分正电荷，氧带等量负电荷。这些基本相关的方法支持了SO−光剥离出口通道中的电子-偶极子相互作用在形成pad中起重要作用的结论。而对于CN−的σ轨道的光脱离，先前也得到了类似的结论。化学。列托人。， 2012,12, 10086-10092)，目前的工作包括首次将偶极子场模型扩展到脱离π*轨道。
Photoelectron angular distributions (PADs) in SO− photodetachment using linearly polarized 355 nm (3.49 eV), 532 nm (2.33 eV), and 611 nm (2.03 eV) light were investigated via photoelectron imaging spectroscopy. The measurements at 532 and 611 nm access the X3Σ− and a1Δ electronic states of SO, whereas the measurements at 355 nm also access the b1Σ+ state. In aggregate, the photoelectron anisotropy parameter values follow the general trend with respect to electron kinetic energy (eKE) expected for π*-orbital photodetachment. The trend is similar to O2−, but the minimum of the SO− curve is shifted to smaller eKE. This shift is mainly attributed to the exit-channel interactions of the departing electron with the dipole moment of the neutral SO core, rather than the differing shapes of the SO− and O2− molecular orbitals. Of the several ab initio models considered, two approaches yield good agreement with the experiment: one representing the departing electron as a superposition of eigenfunctions of a point dipole-field Hamiltonian, and another describing the outgoing electron in terms of Coulomb waves originating from two separated charge centers, with a partial positive charge on the sulfur and an equal negative charge on the oxygen. These fundamentally related approaches support the conclusion that electron–dipole interactions in the exit channel of SO− photodetachment play an important role in shaping the PADs. While a similar conclusion was previously reached for photodetachment from σ orbitals of CN− (Hart, Lyle, Spellberg, Krylov, Mabbs, J. Phys. Chem. Lett., 2021, 12, 10086–10092), the present work includes the first extension of the dipole-field model to detachment from π* orbitals.