Valence and Core-Level X-ray Photoelectron Spectroscopy of a Liquid Ammonia Microjet
Valence and Core-Level X-ray Photoelectron Spectroscopy of a Liquid Ammonia Microjet
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DOI：
10.1021/jacs.8b10942
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发表时间：
2019-02-06
影响因子：
15
通讯作者：
Bradforth, Stephen E.
中科院分区：
文献类型：
--
作者：
Buttersack, Tillmann;Mason, Philip E.;Bradforth, Stephen E.
膨胀到真空中的微射流的光电子能谱可以获得液体中溶质或溶剂分子的轨道能量。以前已经研究过水、乙腈和醇的微射流；然而，还不清楚是否可以实现低温分子溶剂的射流。在这里，我们展示了在真空中稳定的20微米液氨喷流(-60摄氏度)，我们用它来记录价能级和核心能级的光电子能谱，并使用软X射线同步辐射。观察到气相中孤立的氨气发生了显著的位移，而液态光电子角各向异性也是如此。与团簇和固相中的氨的光谱以及不同相中的水的光谱进行比较，可能揭示氢键是如何反映在凝聚相电子结构中的。
Photoelectron spectroscopy of microjets expanded into vacuum allows access to orbital energies for solute or solvent molecules in the liquid phase. Microjets of water, acetonitrile and alcohols have previously been studied; however, it has been unclear whether jets of low temperature molecular solvents could be realized. Here we demonstrate a stable 20 mu m jet of liquid ammonia (-60 degrees C) in a vacuum, which we use to record both valence and core-level band photoelectron spectra using soft X-ray synchrotron radiation. Significant shifts from isolated ammonia in the gas-phase are observed, as is the liquid phase photoelectron angular anisotropy. Comparisons with spectra of ammonia in clusters and the solid phase, as well as spectra for water in various phases potentially reveal how hydrogen bonding is reflected in the condensed phase electronic structure.