Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, CZ-12116 Prague 2, Czech Republic.
Faraday Discuss. 2009;142:191-201; discussion 221-55. doi: 10.1039/b822769c.
We explore the potential energy surfaces for NH molecules interacting with alkali-metal and alkaline-earth atoms using highly correlated ab initio electronic structure calculations. The surfaces for interaction with alkali-metal atoms have deep wells dominated by covalent forces. The resulting strong anisotropies will produce strongly inelastic collisions. The surfaces for interaction with alkaline-earth atoms have shallower wells that are dominated by induction and dispersion forces. For Be and Mg the anisotropy is small compared to the rotational constant of NH, so that collisions will be relatively weakly inelastic. Be and Mg are thus promising coolants for sympathetic cooling of NH to the ultracold regime.
我们使用高相关的从头算电子结构计算方法探索了 NH 分子与碱金属和碱土金属原子相互作用的势能面。与碱金属原子相互作用的表面具有由共价力主导的深势阱。由此产生的强烈各向异性将产生强烈的非弹性碰撞。与碱土金属原子相互作用的表面势阱较浅，主要由感应和色散力主导。对于 Be 和 Mg，与 NH 的转动常数相比，各向异性较小，因此碰撞将相对较弱。因此，Be 和 Mg 是 NH 向超低温区的 sympathetic 冷却的有前途的冷却剂。
