Ganesan-Santhi Sangami, Frye Matthew D, Gronowski Marcin, Tomza Michał
Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland.
J Phys Chem A. 2025 Sep 11;129(36):8239-8250. doi: 10.1021/acs.jpca.5c02533. Epub 2025 Sep 2.
Aluminum monofluoride (AlF) is a promising candidate for laser cooling and the production of dense ultracold molecular gases, thanks to its relatively high chemical stability and diagonal Franck-Condon factors. In this study, we examine the interactions and collisions of AlF in its Σ, Π, and Π electronic states with ground-state He using state-of-the-art ab initio quantum chemistry techniques. We construct accurate potential energy surfaces (PESs) employing either the explicitly correlated coupled-cluster CCSD(T)-F12 method augmented by the CCSDT correction or the multireference configuration-interaction method for higher-excited electronic states. Subsequently, we employ these PESs in coupled-channel calculations to determine the scattering cross sections for AlF + He collisions and bound states of the complex. We estimate the uncertainty of the calculated PESs and apply it to assess the uncertainty of the scattering results. We find a relatively low sensitivity of the cross sections to the variation of the PESs, but the positions of shape resonances remain uncertain. The present results are relevant for further improvements and optimizations of buffer-gas cooling of AlF molecules.
一氟化铝（AlF）因其相对较高的化学稳定性和对角弗兰克-康登因子，是激光冷却和产生高密度超冷分子气体的一个有前景的候选物质。在本研究中，我们使用最先进的从头算量子化学技术，研究处于Σ、Π和Π电子态的AlF与基态He的相互作用和碰撞。我们采用通过CCSDT校正增强的显式相关耦合簇CCSD(T)-F12方法或用于更高激发电子态的多参考组态相互作用方法，构建精确的势能面（PES）。随后，我们在耦合通道计算中使用这些PES来确定AlF + He碰撞的散射截面和复合物的束缚态。我们估计计算得到的PES的不确定性，并将其应用于评估散射结果的不确定性。我们发现截面对于PES变化的敏感性相对较低，但形状共振的位置仍然不确定。目前的结果对于进一步改进和优化AlF分子的缓冲气体冷却具有重要意义。
