题目：The primary steps of ion solvation in a liquid helium nanodroplet
报告人：Henrik Stapelfeldt 教授
主持人：吴健 教授
时间：2025年5月9日08:30至10:00
地点：闵行校区光学大楼B325会议室
报告人简介：
Henrik Stapelfeldt教授1993年博士毕业于丹麦Aarhus大学，1993年到2000年在Aarhus大学担任助理教授，期间1994年到1996年在加拿大渥太华国家研究委员会从事博士后研究，2000年晋升为副教授，2009年晋升为教授，2007年当选美国物理学会会士，2020年当选丹麦皇家科学与文学院院士。Stapelfeldt教授是分子排列以及氦纳米液滴中的超快物理方面的国际权威专家，迄今发表科技论文150余篇，被引近万次，H因子达58。
报告内容简介：
Solvation is an omnipresent process both in our daily life and in the natural sciences. At the atomic level, the primary steps of solvation are the attraction and binding of ions or molecules of a solute to molecules or atoms of a solvent. Until recently, these steps had not been observed in real time.
I will present experimental results that have enabled us to observe the solvation dynamics of a single alkali cation in liquid helium with atomic resolution and on the natural femtosecond time scale [1,2]. A single Li+, Na+, or K+ ion is created instantly at the surface of a nanometer-sized droplet of liquid helium and we measured in real time the gradual attachment of individual He atoms to the ion. In the case of Na+, we found that the binding of the first 5 He atoms occurs at a rate of 1.8 atoms/ps, which is consistent with time-dependent density-functional-theory simulations.
In addition, we determined the time-dependence of the energy dissipated from the local region around the alkali ion during its solvation. We found that it follows Newton's law of cooling for the first 5 ps [2].
The experimental methodology applied opens opportunities for exploring in real time the noncovalent bonding of cations to molecules.
[1]S. H. Albrechtsen, C. A. Schouder, A. Viñas Muñoz, J. K. Christensen, C. Engelbrecht Petersen, M. Pi, M. Barranco and H. Stapelfeldt, Nature 623, 319 (2023)
[2]S. H. Albrechtsen, J. K. Christensen, C. Engelbrecht Petersen, C. A. Schouder, P. J. Carchi-Villalta, I. Sanchez-Perez, M. Bartolomei, T. Gonzalez-Lezana, F. Pirani and H. Stapelfeldt, submitted (2025), https://arxiv.org/abs/2502.11783