Czekner Joseph, Lopez Gary V, Wang Lai-Sheng
Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
J Chem Phys. 2014 Dec 28;141(24):244302. doi: 10.1063/1.4904269.
We report a study of the electronic and vibrational structures of the gaseous uranium monoxide and dioxide molecules using high-resolution photoelectron imaging. Vibrationally resolved photoelectron spectra are obtained for both UO(-) and UO2(-). The spectra for UO2(-) are consistent with, but much better resolved than a recent study using a magnetic-bottle photoelectron analyzer [W. L. Li et al., J. Chem. Phys. 140, 094306 (2014)]. The electron affinity (EA) of UO is reported for the first time as 1.1407(7) eV, whereas a much more accurate EA is obtained for UO2 as 1.1688(6) eV. The symmetric stretching modes for the neutral and anionic ground states, and two neutral excited states for UO2 are observed, as well as the bending mode for the neutral ground state. These vibrational frequencies are consistent with previous experimental and theoretical results. The stretching vibrational modes for the ground state and one excited state are observed for UO. The current results for UO and UO2 are compared with previous theoretical calculations including relativistic effects and spin-orbit coupling. The accurate experimental data reported here provide more stringent tests for future theoretical methods for actinide-containing species.
我们报道了一项利用高分辨率光电子成像技术对气态一氧化铀和二氧化铀分子的电子结构与振动结构进行的研究。获得了UO⁻和UO₂⁻的振动分辨光电子能谱。UO₂⁻的能谱与最近一项使用磁瓶光电子分析仪的研究结果一致[W. L. Li等人，《化学物理杂志》140, 094306 (2014)]，但分辨率更高。首次报道UO的电子亲和能（EA）为1.1407(7) eV，而UO₂的EA值更为精确，为1.1688(6) eV。观察到UO₂中性和阴离子基态的对称伸缩模式、两个中性激发态，以及中性基态的弯曲模式。这些振动频率与先前的实验和理论结果一致。观察到UO基态和一个激发态的伸缩振动模式。将UO和UO₂的当前结果与包括相对论效应和自旋轨道耦合在内的先前理论计算进行了比较。这里报道的精确实验数据为未来含锕系元素物种的理论方法提供了更严格的检验。
