Ndione Pascal D, Weber Sebastian T, Gericke Dirk O, Rethfeld Baerbel
Department of Physics and OPTIMAS Research Center, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 46, 67663, Kaiserslautern, Germany.
Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry, CV4 7AL, UK.
Sci Rep. 2022 Mar 18;12(1):4693. doi: 10.1038/s41598-022-08338-2.
Free electron lasers offer unique properties to study matter in states far from equilibrium as they combine short pulses with a large range of photon energies. In particular, the possibility to excite core states drives new relaxation pathways that, in turn, also change the properties of the optically and chemically active electrons. Here, we present a theoretical model for the dynamics of the nonequilibrium occupation of the different energy bands in solid gold driven by exciting deep core states. The resulting optical response is in excellent agreement with recent measurements and, combined with our model, provides a quantitative benchmark for the description of electron-phonon coupling in strongly driven gold. Focusing on sub-picosecond time scales, we find essential differences between the dynamics induced by XUV and visible light.
自由电子激光具有独特的特性，能够研究远离平衡态的物质，因为它们将短脉冲与大范围的光子能量结合在一起。特别是，激发核心态的可能性驱动了新的弛豫途径，进而也改变了光学和化学活性电子的性质。在此，我们提出了一个理论模型，用于描述由激发深核心态驱动的固体金中不同能带的非平衡占据动力学。由此产生的光学响应与最近的测量结果非常吻合，并且结合我们的模型，为强驱动金中电子-声子耦合的描述提供了一个定量基准。聚焦于亚皮秒时间尺度，我们发现了极紫外光（XUV）和可见光诱导的动力学之间的本质差异。
