【校级报告】分子动力学的成像与调控

报告题目：分子动力学的成像与调控

报告人：李铮 研究员

报告人单位：北京大学物理学院

主持人：张文斌 研究员

时间：2024年11月27日（周三）下午15:00

地点：光学大楼A508会议室

报告摘要：

The Jahn-Teller effect is a fundamental mechanism of spontaneous symmetry breaking in molecular and solid state systems, and has far-reaching consequences in many fields. Up to now, to directly image the onset of Jahn-Teller symmetry breaking remains unreached. Here we employ ultrafast ion-coincidence Coulomb explosion imaging with sub-10 fs resolution and unambiguously image the ultrafast dynamics of Jahn-Teller deformations of CH₄⁺ cation in symmetry space. It is unraveled that the Jahn-Teller deformation from C_3v to C_2v geometries takes a characteristic time of 20+/-7 fs for this system. Classical and quantum molecular dynamics simulations agree well with the measurement, and reveal dynamics for the build-up of the C_2v structure involving complex revival process of multiple vibrational pathways of the CH₄⁺ cation.

At the same time, we have proposed an analysis method for ultrafast diffraction imaging, which can be used to reconstruct the quantum state of molecular dynamics processes. And through external field control and quantum Zeno effect, we have achieved a selection of quantum states in the molecular dynamics process.

报告人简介：

李铮，北大物理学院研究员，助理教授。分别于北京大学和德国汉堡大学/DESY获得学士和博士学位；先后在德国DESY、美国斯坦福大学、德国马普所等从事博士后和课题组长工作。主要从事第一性原理原子分子结构理论，分子动力学，自由电子激光，和光与物质相互作用领域的理论研究，着重于研究与自由电子激光相关的理论，在Science, Phys. Rev. Lett., Nature Commun., J. Am. Chem. Soc., Sci. Adv.等杂志发表研究论文六十余篇。