Institut des Sciences Moléculaire d'Orsay (CNRS), Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France.
Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
J Chem Phys. 2018 Jul 21;149(3):034308. doi: 10.1063/1.5030621.
In this paper, we investigate HNCO by resonant and nonresonant Auger electron spectroscopy at the K-edges of carbon, nitrogen, and oxygen, employing soft X-ray synchrotron radiation. In comparison with the isosteric but linear CO molecule, spectra of the bent HNCO molecule are similar but more complex due to its reduced symmetry, wherein the degeneracy of the π-orbitals is lifted. Resonant Auger electron spectra are presented at different photon energies over the first core-excited 1s → 10a' resonance. All Auger electron spectra are assigned based on ab initio configuration interaction computations combined with the one-center approximation for Auger intensities and moment theory to consider vibrational motion. The calculated spectra were scaled by a newly introduced energy scaling factor, and generally, good agreement is found between experiment and theory for normal as well as resonant Auger electron spectra. A comparison of resonant Auger spectra with nonresonant Auger structures shows a slight broadening as well as a shift of the former spectra between -8 and -9 eV due to the spectating electron. Since HNCO is a small molecule and contains the four most abundant atoms of organic molecules, the reported Auger electron decay spectra will provide a benchmark for further theoretical approaches in the computation of core electron spectra.
在本文中，我们通过共振和非共振俄歇电子能谱在碳、氮和氧的 K 边，利用软 X 射线同步辐射，研究了 HNCO。与等电子但线性 CO 分子相比，由于其对称性降低，其中π轨道的简并性被解除，弯曲的 HNCO 分子的光谱相似但更复杂。我们给出了在第一个核心激发 1s → 10a' 共振过程中不同光子能量下的共振俄歇电子能谱。所有俄歇电子能谱都基于从头计算组态相互作用计算以及用于俄歇强度的单中心近似和考虑振动运动的矩理论进行了分配。通过引入新的能量标度因子对计算光谱进行了标度，实验和理论在正常和共振俄歇电子能谱之间通常都存在良好的一致性。共振俄歇光谱与非共振俄歇结构的比较表明，由于观测电子的存在，前者的光谱在 -8 和 -9 eV 之间稍微变宽并且发生了位移。由于 HNCO 是一个小分子并且包含有机分子中最丰富的四个原子，因此报告的俄歇电子衰减光谱将为进一步在核心电子光谱的计算中采用理论方法提供基准。
