Theoretical and experimental studies of nuclear displacement relaxation process induced by core excitation

根据研究计划，我们进行了如下研究。本项目主要包括三个方面的内容：1）轻元素材料核激发态的核弛豫动力学; 2）俄歇完全态的核弛豫动力学; 3）利用核激发进行材料操控的实验探索。相应于每一个课题，我们得到了以下结果：1）我们成功地用扩展的电子振动模型，充分考虑了激发态电子的量子转移，从理论上解释了石墨的X射线吸收谱和共振谱中的极化相关的光谱特征。此外，我们首次发现了在高能X射线激发下能清楚地观察到的光电发射过程中深刻的反冲效应。这些理论发现已经在最近的实验中得到了证实。2）为了从俄歇末态理解弛豫动力学，需要高精度地揭示俄歇末态中的许多电子态。双电离的芯激发态常常离域在激发原子位置周围的几个中心上。Uozumi等人发展了一个基于双位杂质安德森模型的理论，该理论考虑了多重态相互作用和组态相互作用，并解释了过渡金属化合物的芯能级谱实验。3）Harad测量了生物分子中O ~+和N ~+的共振X射线谱，揭示了对生物功能起关键作用的电子结构。

According to the plan of the study, we have proceeded our research as follows. We set up three major targets in this project: 1) Nuclear relaxation dynamics in core excited states of light element materials, 2) Nuclear relaxation dynamics from Auger completed state, 3) Experimental quest for material manipulation with use of core excitation. Corresponding to each subjects we have obtained the following results.1) We have succeeded in theoretically explaining the spectral features of xray absorption spectrum of graphite and polarization correlation in the resonant my spectrum in terms of extended vibronic model in which quantum transfer of the excited electron is fully taken into account. We furthermore, first found the profound recoil effect in the photoemission process which is clearly observed in the high energy xray excitation. These theoretical finding has been confirmed in the recent experiments.2) In order to understand the relaxation dynamics from the Auger final state, it is necessary to reveal the many electron states in the Auger final state with high accuracy. It often happens that the doubly ionized core excited states are delocalized over several centers around the excited atomic site. Uozumi have developed a theory based on two-site impurity Anderson model in which multiplet interaction and configuration interaction are taken into account, and explained the experiments of core level spectrum of transition metallic compounds.3) Harad measured O is and N is resonant x-ray spectrum in biomolecules and revealed the electronic structure which plays a key role to the biofunctions.