| 报告题目 | Resonant Auger spectroscopy of the nuclear dynamics induced by intense ultrashort delayed x-ray pulses |
| 报告人 | 张松斌 博士 |
| 报告人单位 | Max Planck Institute for the Physics of Complex Systems & Center for Free Electron Laser Science |
| 报告时间 | 2014-12-23 |
| 报告地点 | 合肥微尺度物质科学国家实验室九楼会议室(9004室) |
| 主办单位 | 合肥微尺度物质科学国家实验室 |
| 报告介绍 | 报告摘要：
Ultrashort intense x-ray pulses available from new XFEL and HHG light sources allows to employ ultrafast and non-linear processes in atoms and molecules for probing quantum coherence effects and electron correlations on core-to-valence transitions [1]. The strong x-ray field can sufficiently alter the vibronic dynamics in the system, which is reflected particularly in the significant changes of the Auger decay spectra [2-4]. In the present work, we combine the two complementary techniques – stimulated x-ray Raman scattering and resonant Auger scattering –to unveil complex electronic and nuclear dynamics in molecular system triggered by a pair of pump-dump ultrashort x-ray pulses. Here we use an aligned CO molecule as an example. A 2 fs weak pump pulse resonantly creates the core excited C(1s-1π*)O molecule. This highly excited electronic state is resonantly coupled to a valence excited state by a second detuned x-ray dump pulse. With the help of the delay control between the pump and dump pulses one can effectively control the dynamics of the core-excited and final electronic states (Fig.1). Our numerical simulations show that simultaneous Auger decay of the core-excited state alters sufficiently depending on the delay time and it can be used for an advanced characterization of the wave packet dynamics [5]. Fig. 2 shows the Auger spectra for different time delays (the Rabi frequencies for the pump and dump are 0.005 and 0.05 a.u., respectively, and fixed; the dump frequency is tuned to be 277.6 eV). One clearly see that the Auger spectra can be controlled and significantly changed by the effect of the dump pulse (Fig. 2b), which can be explained by the temporal evolutions of vibrational populations altered by the dump pulse in the core excited and final states.
References:
[1] S. Mukamel et al., Annu. Rev. Phys. Chem. 64,101 (2013)
[2] N. Rohringer and R. Santra, Phys. Rev. A 77, 053404 (2008)
[3] J.-C. Liu et al., Phys. Rev. A 81, 043412 (2010)
[4] P. Demekhin et al., Phys. Rev. A 84, 033417 (2011)
[5] S. B. Zhang, V. Kimberg and N. Rohringer (2014, in preparation)
报告人简介：
1984年出生于湖北大冶，2007年四川大学物理学本科毕业，2011年中国科学技术大学—北京应用物理与计算数学研究所联合培养理学博士毕业，曾获2010年中国科学院院长优秀奖。 2011.06-2012.07期间，在美国Texas A&M University化学系从事博士后研究；2012.07起到现在，在德国Max Planck Institute for the Physics of Complex Systems & Center for Free Electron Laser Science从事博士后研究。主要从事传统的原子分子结构和动力学过程，以及现代的超快强场激光物理应用的理论研究：包括原子分子的结构，电子/光与原子分子的碰撞激发电离，激光取向，高次谐波，时间分辨的光电子谱学，超快波包动力学演化等等。以第一作者在Phys. Rev. Lett.、Phys. Rev. A等重要国际学术期刊上发表SCI论文十几篇。也是Phys. Rev. Lett.和Phys. Rev. A等期刊的审稿人。 |
