Li Hui, Li Ming, Petrov Alexander, Tiesinga Eite, Kotochigova Svetlana
Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States.
Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899, United States.
J Phys Chem A. 2023 Jul 27;127(29):5979-5985. doi: 10.1021/acs.jpca.3c00242. Epub 2023 Jul 12.
Conical intersections are crossing points or lines between two or more adiabatic electronic potential energy surfaces in the multidimensional coordinate space of colliding atoms and molecules. Conical intersections and corresponding nonadiabatic coupling can greatly affect molecular dynamics and chemical properties. In this paper, we predict significant or measurable nonadiabatic effects in an ultracold atom-ion charge-exchange reaction in the presence of laser-induced conical intersections (LICIs). We investigate the fundamental physics of these LICIs on molecular reactivity under unique conditions: those of relatively low laser intensity of 10 W/cm and ultracold temperatures below 1 mK. We predict irregular interference effects in the charge-exchange rate coefficients between K and Ca as functions of the laser frequency. These irregularities occur in our system due to the presence of two LICIs. To further elucidate the role of the LICIs on the reaction dynamics, we compare these rate coefficients with those computed for a system where the CIs have been "removed". In the laser frequency window, where conical interactions are present, the difference in rate coefficients can be as large as 1 × 10 cm/s.
锥形交叉点是碰撞原子和分子的多维坐标空间中两个或多个绝热电子势能面之间的交叉点或交叉线。锥形交叉点和相应的非绝热耦合会极大地影响分子动力学和化学性质。在本文中，我们预测在存在激光诱导锥形交叉点（LICIs）的超冷原子 - 离子电荷交换反应中会出现显著或可测量的非绝热效应。我们在独特条件下研究这些LICIs对分子反应性的基本物理过程：激光强度相对较低为10 W/cm且温度低于1 mK的超冷温度条件。我们预测K和Ca之间电荷交换速率系数随激光频率变化会出现不规则干涉效应。由于存在两个LICIs，这些不规则性在我们的系统中出现。为了进一步阐明LICIs对反应动力学的作用，我们将这些速率系数与为“去除”锥形交叉点的系统计算得到的速率系数进行比较。在存在锥形相互作用的激光频率窗口中，速率系数的差异可能高达1×10 cm/s。
