We present a study of vibrational quenching and chemical processes of molecular ions immersed in an ultracold atomic gas by means of the quasi-classical trajectory (QCT) method. In particular, BaRb$^+(v)$ + Rb collisions are studied at cold temperatures revealing a highly efficient energy transfer between the translational degrees of freedom and internal degrees of the molecular ion. Thus leading to a large vibrational quenching cross section which follows the Langevin capture model prediction. These results play a key role on the understanding of relaxation phenomena of cold molecular ions in ultracold gases as well as in the fate of the molecules emerging trough ion-neutral-neutral three-body recombination in an cold and dense environment.
Sensitive detection of metastable NO and \ce{N2} by reactive collisions with laser-excited Li
在原理验证实验中，我们证明了亚稳态一氧化氮分子，NO（$^4Π_i$），脉冲，超声束内产生的，可以检测到的反应气相碰撞与电子激发的锂原子的$2^2$ P $_{3/2}$状态。由于NO（a $^4Π_i$，$v \leq 4$）的内能低于$2^2$ S $_{1/2}$电子基态中Li的电离势，我们观察到自电离NO（a $^4Π_i$）+Li（$2^2$ S $_{1/2}$）碰撞产生的产物离子产率比NO（a $^4Π_i$）+Li（$2^2$ P $_{3/2}$）碰撞产生的离子产率低21倍。我们还比较了我们的研究结果与测量的亚稳态\ce{N2} +锂（$2^2$ S $_{1/2}$）和亚稳态\ce{N2} +锂（$2^2$ P $_{3/2}$）反应碰撞的相对速率。使用这种检测方法，我们推断在相互作用区域中$\approx 600$ NO（a $^4Π_i$）分子/cm $^3$和$\approx 6 \cdot 10^{4}$亚稳\ce{N2}分子/cm $^3$的密度。我们的研究结果还允许一个估计的分数人口NO（$^4Π_i$，$v \geq 5$）之前的碰撞过程。从X $^2Π_r$基态用激光激发产生选定振动态的NO（a $^4Π_i$）将为详细研究振动态选定的NO（a $^4Π_i$）-Li（$2^2$ P $_{3/2}$）碰撞提供可能性。
Quenching of $para$-H$_2$ with an ultra-cold anti-hydrogen atom $\bar{H}_{1s}$
本文报道了超冷基态反氢原子$\bar{H}_{1s}$诱导的氢分子H $_2$的量子力学转动跃迁的计算结果。计算是使用非反应性紧密耦合量子力学方法完成的。H $_2$分子被视为刚性转子。在0.004 K $ \lesssim T \lesssim$ 4 K温度范围内计算了能量$ε$处的总弹性散射截面$σ_{el}(ε)$、$j$和$j'$之间的态分辨转动跃迁截面$σ_{jj'}(ε)$以及相应的热速率系数$k_{jj'}(T)$.对$σ_{el}(ε)$的计算结果与其它计算结果（变分）吻合得很好。
