在FLASH通过极紫外光泵浦红外光探测实验追踪氩二聚体中的电荷转移

Tracing charge transfer in argon dimers by XUV-pump IR-probe experiments at FLASH.

作者信息

Schmid Georg, Schnorr Kirsten, Augustin Sven, Meister Severin, Lindenblatt Hannes, Trost Florian, Liu Yifan, Miteva Tsveta, Gisselbrecht Mathieu, Düsterer Stefan, Redlin Harald, Treusch Rolf, Gokhberg Kirill, Kuleff Alexander I, Cederbaum Lorenz S, Schröter Claus Dieter, Pfeifer Thomas, Moshammer Robert

机构信息

Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.

Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany.

出版信息

J Chem Phys. 2019 Aug 28;151(8):084314. doi: 10.1063/1.5116234.

DOI:10.1063/1.5116234

PMID:31470702

Abstract

Charge transfer (CT) at avoided crossings of excited ionized states of argon dimers is observed using a two-color pump-probe experiment at the free-electron laser in Hamburg (FLASH). The process is initiated by the absorption of three 27-eV-photons from the pump pulse, which leads to the population of Ar-Ar states. Due to nonadiabatic coupling between these one-site doubly ionized states and two-site doubly ionized states of the type Ar-Ar, CT can take place leading to the population of the latter states. The onset of this process is probed by a delayed infrared (800 nm) laser pulse. The latter ionizes the dimers populating repulsive Ar -Ar states, which then undergo a Coulomb explosion. From the delay-dependent yields of the obtained Ar and Ar ions, the lifetime of the charge-transfer process is extracted. The obtained experimental value of (531 ± 136) fs agrees well with the theoretical value computed from Landau-Zener probabilities.

摘要

在汉堡自由电子激光装置（FLASH）上，通过双色泵浦 - 探测实验观测到了氩二聚体激发电离态的避免交叉处的电荷转移（CT）。该过程由泵浦脉冲吸收三个27电子伏特的光子引发，这导致了Ar - Ar态的布居。由于这些单中心双电离态与Ar - Ar型双中心双电离态之间的非绝热耦合，电荷转移能够发生，从而导致后者态的布居。此过程的起始由延迟的红外（800纳米）激光脉冲探测。后者使二聚体电离，使其布居到排斥性的Ar - Ar态，然后这些态会经历库仑爆炸。从所获得的Ar⁺和Ar²⁺离子的与延迟相关的产率中，提取出电荷转移过程的寿命。所获得的（531 ± 136）飞秒的实验值与根据朗道 - 齐纳概率计算出的理论值吻合良好。