The prospect of cooling matter down to temperatures that are close to absolute zero raises intriguing questions about how chemical reactivity changes under these extreme conditions. Although some types of chemical reaction still occur at 1 μK, they can no longer adhere to the conventional picture of reactants passing over an activation energy barrier to become products. Indeed, at ultracold temperatures, the system enters a fully quantum regime, and quantum mechanics replaces the classical picture of colliding particles. In this Review, we discuss recent experimental and theoretical developments that allow us to explore chemical reactions at temperatures that range from 100 K to 500 nK. Although the field is still in its infancy, exceptional control has already been demonstrated over reactivity at low temperatures.

将物质冷却到接近绝对零的温度的前景引发了关于在这些极端条件下化学反应性如何变化的有趣问题。尽管某些类型的化学反应仍会在 1 μK 下发生，但它们不再符合反应物通过活化能势垒成为产物的传统图景。事实上，在超冷温度下，系统进入完全量子态，量子力学取代了粒子碰撞的经典图景。在这篇综述中，我们讨论了最近的实验和理论发展，这些发展使我们能够探索 100 K 至 500 nK 温度范围内的化学反应。尽管该领域仍处于起步阶段，但已经证明了对低温反应性的出色控制。