论文标题
使用州到州超低化学的统计动力学精确测试
Precision test of statistical dynamics with state-to-state ultracold chemistry
论文作者
论文摘要
化学反应代表了一类量子问题，这些问题既挑战当前的理论理解和计算能力。在超高温度下发生的反应为量子化学和散射理论提供了理想的测试地面，因为它们可以通过前所未有的对照进行实验研究，但表现出高度复杂的动力学。在这里，我们报告了反应2krb $ \ rightarrow $ k $ _2 $ + rb $ _2 $的完整产品状态分布。反应物的超速制备可以完全控制其初始量子自由度，同时对两种产品的状态分辨，一致的检测可以使散射概率的测量纳入所有57个允许的旋转状态对。我们的结果表明，基于统计理论的州计数模型的总体协议，但也揭示了几个偏差的状态对。特别是，我们观察到最接近外部势能限制的州对中的人口的强烈抑制，我们确切地确定$ 9.7711^{+0.0007} _ { - 0.0005} $ CM $ $^{ - 1} $，由于远距离潜在抑制产品的逃生而产生的结果。我们测量的完整性为量子动力学计算提供了一个宝贵的基准。
Chemical reactions represent a class of quantum problems that challenge both the current theoretical understanding and computational capabilities. Reactions that occur at ultralow temperatures provide an ideal testing ground for quantum chemistry and scattering theories, as they can be experimentally studied with unprecedented control, yet display dynamics that are highly complex. Here, we report the full product state distribution for the reaction 2KRb $\rightarrow$ K$_2$ + Rb$_2$. Ultracold preparation of the reactants grants complete control over their initial quantum degrees of freedom, while state-resolved, coincident detection of both products enables the measurement of scattering probabilities into all 57 allowed rotational state-pairs. Our results show an overall agreement with a state-counting model based on statistical theory, but also reveal several deviating state-pairs. In particular, we observe a strong suppression of population in the state-pair closest to the exoergicity limit, which we precisely determine to be $9.7711^{+0.0007}_{-0.0005}$ cm$^{-1}$, as a result of the long-range potential inhibiting the escape of products. The completeness of our measurements provides a valuable benchmark for quantum dynamics calculations beyond the current state-of-the-art.
