WikiEdge:ArXiv速遞/2025-02-17

摘要

• 原文標題：Femtosecond-and-atom-resolved solvation dynamics of a Na$^+$ ion in a helium nanodroplet
• 中文標題：氦納米液滴中鈉離子的飛秒和原子級分辨溶劑化動力學
• 發布日期：2025-02-17 13:17:09+00:00
• 作者：Simon H. Albrechtsen, Jeppe K. Christensen, Christian E. Petersen, Constant A. Schouder, Pedro Javier Carchi-Villalta, Iker Sánchez-Pérez, Massimiliano Bartolomei, Tomás González-Lezana, Fernando Pirani, Henrik Stapelfeldt
• 分類：physics.atm-clus
• 原文鏈接：http://arxiv.org/abs/2502.11783v1

原文摘要：Recently, it was shown how the primary steps of solvation of a single Na$^+$ ion, instantly created at the surface of a nanometer-sized droplet of liquid helium, can be followed at the atomic level [Albrectsen et al. Nature $\textbf{623}$, 319 (2023)]. This involved measuring, with femtosecond time resolution, the gradual attachment of individual He atoms to the Na$^+$ ion as well as the energy dissipated from the local region of the ion. In the current work, we provide a more comprehensive and detailed description of the experimental findings of the solvation dynamics, and present an improved Poisson-statistical analysis of the time-resovled yields of the solvation complexes, Na$^+$He$_n$. For droplets containing an average of 5200 He atoms, this analysis gives a binding rate of $1.84\pm0.09$ atoms/ps for the binding of the first five He atoms to the Na$^+$ ion. Also, thanks to accurate heoretical values for the evaporation energies of the Na$^+$He$_n$ complexes, obtained by Path Integral Monte Carlo methos using a new potential energy surface presented here for the first time, we improved the determination of the time-dependent removal of the solvation energy from the region around the sodium ion. We find that it follows Newton's law of cooling for the first 6 ps. Measurements were carried out for three different average droplet sizes, $\langle N_D\rangle = $ 9000, 5200 and 3600 helium atoms, and differences between these results are discussed. 中文摘要：最近的研究展示了如何在原子水平上跟蹤單個Na$^+$離子在納米級液氦液滴表面瞬間形成時的溶劑化初始步驟 [Albrectsen et al. Nature $\textbf{623}$, 319 (2023)]。這包括以飛秒時間分辨率測量單個He原子逐漸附着到Na$^+$離子的過程，以及從離子局部區域耗散的能量。在當前的工作中，我們提供了對溶劑化動力學實驗結果的更全面和詳細的描述，並對溶劑化複合物Na$^+$He$_n$的時間分辨產率進行了改進的泊松統計分析。對於平均含有5200個He原子的液滴，該分析得出前五個He原子與Na$^+$離子結合的結合速率為$1.84\pm0.09$原子/皮秒。此外，得益於通過路徑積分蒙特卡羅方法獲得的新勢能面，我們首次獲得了Na$^+$He$_n$複合物的蒸發能量的精確理論值，從而改進了對鈉離子周圍區域溶劑化能量隨時間去除的測定。我們發現，在前6皮秒內，它遵循牛頓冷卻定律。測量在三種不同平均液滴尺寸下進行，$\langle N_D\rangle = $ 9000、5200和3600個氦原子，並討論了這些結果之間的差異。