Anisotropy and relaxation dynamics in core-excited small molecules

(1)为了研究核心受激分子的电子衰变和离解动力学，我们开发了一种装置，可以进行角度分辨光电子/俄歇电子能谱、角度分辨离子能谱和能量选择电子-能量选择离子符合。(2)我们在筑波光子工厂进行了一系列实验，阐明了核激发分子的极化/取向如何影响电子衰变和解离动力学。具体而言，我们发现：1)当D_<3h>平面分子BF_3和BC_<l3>时，分子变形以特定核心激发态的方式发生，并影响随后的分子解离。2)高分辨率共振俄歇谱可以探测到核激发态中与分子变形相关的核运动。(3) CF_4和SF_6等高对称分子的F为核激发引起振动耦合导致对称破缺，导致各向异性分子断裂。4) BF_3中的b1s、PF_3和PF_5中的p2p和SF_6中的s2p光电子发射的各向异性受形状共振的强烈影响。5) PF_5中p2p激发后的离子碎裂几乎是各向同性的，这是由于p2p核孔衰变导致各向异性的损失。

(1) Aiming to investigate the electronic decay and dissociation dynamics of core excited molecules, we have developed an apparatus that allows us to perform angle-resolved photoelectron/Auger-electron spectroscopy, angle-resolved ion spectroscopy, and energy-selected electron - energy selected ion coincidence.(2) We have carried out a series of experiments at the photon factory in Tsukuba and elucidated how the polarization/orientation of the core-excited molecule affects the electronic decay and dissociation dynamics. Specifically, we found :1) In case of D_<3h> planar molecules BF_3 and BC_<l3>, the molecular deformation occurs in a way that is characteristic to a specific core-excited state and influences the subsequent molecular dissociation.2) The nuclear motion related to the molecular deformation in the core excited state can be detected in the high-resolution resonant Auger spectrum.3) The F is core excitation of highly symmetric molecules such as CF_4 and SF_6 induces symmetry breaking due to vibronic coupling and results in anisotropic molecular fragmentation.4) The anisotropy of the photoelectron emission from B 1s in BF_3, P 2p in PF_3 and PF_5, and S 2p in SF_6 is strongly influenced by the shape resonances.5) Ionic fragmentation is nearly isotropic after P 2p excitation in PF_5 due to loss of the anisotropy via the P 2p core-hole decay.