González-Sánchez Lola, Sanz-Sanz Cristina, Mazo-Sevillano Pablo Del, Jerosimić Stanka V, Dulitz Katrin, Gianturco Francesco
Departamento de Química Física, University of Salamanca, Plaza de los Caídos sn, 37008 Salamanca, Spain.
Unidad Asociada UAM-IFF-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
J Chem Phys. 2025 Aug 7;163(5). doi: 10.1063/5.0282270.
Following the previous study with an extensive range of quantum calculations involving different electronic states of the BN- anion [Dulitz et al., Phys. Scripta 100, 055411 (2025)], we now extend that work by modeling the quantum dynamics of the collision cooling of its rotational states in order to investigate possible paths for bringing this molecular anion down to temperatures of a few Kelvins. This specific ionic system is of direct interest when modeling experiments in cold ion traps where He or Ar atoms can function as the chief buffer gases that drive the anions down to the low trap temperatures. We employ accurate, ab initio calculations of the potential energy surfaces for the title system in its ground electronic state, interacting with either He or Ar atoms. We then obtain a wide range of inelastic cross sections and the ensuing rate coefficients in order to model the quantum kinetics of the time evolution of the cooling steps under different temperature and trap conditions. The results are analyzed and employed to estimate the cooling efficiency paths provided by various trap arrangements for the title anion. The results show that-using either of the two investigated species-the buffer gas cooling process very efficiently brings the anions to their lowest rotational states. These findings are very promising for future applications in the field of anion laser cooling.
继之前涉及BN⁻阴离子不同电子态的广泛量子计算研究[杜利茨等人，《物理学文献》100, 055411 (2025)]之后，我们现在通过对其转动态碰撞冷却的量子动力学进行建模来扩展该工作，以研究将这种分子阴离子冷却至几开尔文温度的可能途径。在模拟冷离子阱中的实验时，这个特定的离子系统具有直接的研究意义，在这些实验中，氦或氩原子可以作为主要的缓冲气体，将阴离子驱动至较低的阱温度。我们对处于基态电子态的标题系统与氦或氩原子相互作用的势能面进行了精确的从头计算。然后，我们获得了广泛的非弹性截面和随之而来的速率系数，以便对不同温度和阱条件下冷却步骤时间演化的量子动力学进行建模。对结果进行分析，并用于估计各种阱配置为标题阴离子提供的冷却效率路径。结果表明，使用所研究的两种物质中的任何一种，缓冲气体冷却过程都能非常有效地将阴离子冷却至其最低转动态。这些发现对于阴离子激光冷却领域的未来应用非常有前景。
