论文标题
在离子分子反应中观察量子捕获
Observation of quantum capture in an ion-molecule reaction
论文作者
论文摘要
1954年，Vogt和Wannier（Phys。Rev.95，1190）预测，与经典的Langevin速率相比，由于碰撞能量接近零，与经典的langevin速率相比，离子的捕获率应增加两倍。该预测尚未通过实验验证。 h $ _2^ + $ + h $ _2 $反应非常适合观察这种效果，因为较小的减少质量会产生与其他系统相比，在更高的碰撞能量下可观察到的S波散射相关的量子效应。此外，这种无障碍，强烈放热的反应的反应速率遵循经典的langevin捕获模型，直至冷碰撞条件（大约$ k_ \ mathrm {b} \ cdot〜1 \，\ mathrm {k} $），并且不受短距离相互作用的影响。低于此温度，观察到了H $ _2^+$和地下盐h $ _2 $（$ j = 1 $）之间的Quadrupole相互作用的强烈提高。在这里，我们介绍了H $ _2^+$和PARA H $ _2 $（$ J = 0 $）的反应的实验研究，该反应没有偶极和四杆矩，在低于$ K_ \ Mathrm {b} \ cdot 1 \，\ cdot 1 \，\ Mathrm {k} $的碰撞能量上。我们观察到最低碰撞能的增强，这归因于Vogt和Wannier预测的量子增强。 HD $^+$与HD的反应的测量支持此结论。
In 1954, Vogt and Wannier (Phys. Rev. 95, 1190) predicted that the capture rate of a polarizable neutral atom or molecule by an ion should increase by a factor of two compared to the classical Langevin rate as the collision energy approaches zero. This prediction has not been verified experimentally. The H$_2^+$ + H$_2$ reaction is ideally suited to observe this effect, because the small reduced mass makes quantum effects related to s-wave scattering observable at higher collision energies than in other systems. Moreover, the reaction rate for this barrierless, strongly exothermic reaction follows the classical Langevin capture model down to cold-collision conditions (about $k_\mathrm{B} \cdot~1\,\mathrm{K}$) and is not affected by short-range interactions. Below this temperature, a strong enhancement of the reaction rate resulting from charge--quadrupole interaction between H$_2^+$ and ground-state ortho H$_2$ ($J=1$) was observed. Here we present an experimental study of the reaction of H$_2^+$ and para H$_2$ ($J=0$), which has no dipole and no quadrupole moments, at collision energies below $k_\mathrm{B}\cdot 1\,\mathrm{K}$. We observe an enhancement at the lowest collision energies which is attributed to the quantum enhancement predicted by Vogt and Wannier. Measurements of the reaction of HD$^+$ with HD support this conclusion.
