Studying chemical reactions on a state-to-state level tests and improves our fundamental understanding of chemical processes. For such investigations it is convenient to make use of ultracold atomic and molecular reactants as they can be prepared in well defined internal and external quantum states. Here, we investigate a single-channel reaction of two Li₂-Feshbach molecules where one of the molecules dissociates into two atoms 2AB ⇒ AB + A + B. The process is a prototype for a class of four-body collisions where two reactants produce three product particles. We measure the collisional dissociation rate constant of this process as a function of collision energy/temperature and scattering length. We confirm an Arrhenius-law dependence on the collision energy, an a⁴ power-law dependence on the scattering length a and determine a universal four body reaction constant.

中文翻译：

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超冷分子-分子碰撞的反应动力学。

在州到州的水平上研究化学反应可以测试并提高我们对化学过程的基本了解。对于此类研究，使用超冷原子和分子反应物很方便，因为它们可以以定义良好的内部和外部量子态进行制备。在这里，我们研究了两个Li ₂ -Feshbach分子的单通道反应，其中一个分子解离为两个原子2AB⇒AB + A +B。该过程是一类四体碰撞的原型，其中两种反应物产生三个产品粒子。我们测量了该过程的碰撞解离速率常数，该常数是碰撞能量/温度和散射长度的函数。我们确定了阿雷尼乌斯定律对碰撞能量的依赖，即⁴ 幂律取决于散射长度a，并确定一个通用的四体反应常数。