Charge Exchange Dynamics in Cold Collisions of $^{40}$CaH$^+$ and $^{39}$K
钙氢离子与钾原子在冷碰撞中的电荷交换动力学
Swapnil Patel, Dibyendu Sardar, Jyothi Saraladevi, Michał Tomza, Kenneth R. Brown
AI总结 研究了钙氢分子离子与超冷钾原子在混合离子-原子陷阱中的电荷交换碰撞,发现其速率系数显著低于兰格vin常数,通过首次原理量子化学计算揭示了电荷交换机制,表明需更全面的量子动力学处理以准确描述碰撞动力学。
详情
- Journal ref
- J. Phys. Chem. Lett. 17, 6574 (2026)
我们报告了在混合离子-原子陷阱中观测到钙单氢分子离子($^{40}$CaH$^+$)与超冷钾原子($^{39}$K)之间的电荷交换碰撞。测量的电荷交换速率系数显著低于该系统的兰格vin速率常数。我们使用首次原理量子化学计算来建模(CaH-K)$^+$复合作用在基态和激发态,并识别可能的电荷交换机制。我们的计算排除了直接非辐射电荷交换反应,而指向辐射机制,但未能定量重现测量速率,突显了需要包含振动运动和中间复合作用的全维量子动力学处理的必要性。我们的工作证明了冷混合离子-原子平台具有分子离子能够访问更丰富的化学复杂性和碰撞动力学,这些在纯原子系统中是无法实现的。
We report the observation of charge-exchange collisions between trapped calcium monohydride molecular ions ($^{40}$CaH$^+$) and ultracold potassium atoms ($^{39}$K) in a hybrid ion-atom trap. The measured charge-exchange rate coefficient is significantly suppressed relative to the Langevin rate constant for the system. We use $\mathit{ab\ initio}$ quantum-chemical calculations to model the (CaH-K)$^+$ complex in the ground and excited electronic states and to identify possible charge-exchange mechanisms. Our calculations rule out a direct non-radiative charge-exchange reaction and instead point to a radiative mechanism, but do not quantitatively reproduce the measured rate, highlighting the need for a full-dimensional quantum dynamics treatment that includes vibrational motion and intermediate complex formation. Our work demonstrates that cold hybrid ion-atom platforms with molecular ions enable access to richer chemical complexity and collisional dynamics inaccessible in purely atomic systems.