Chemical Physics ( IF 2.0 ) Pub Date : 2018-06-25 , DOI: 10.1016/j.chemphys.2018.06.014 Rafael Haenel , Edward Grant
An ellipsoidal volume of Rydberg molecules, entrained in a supersonic molecular beam, evolves on a nanosecond timescale to form a strongly coupled ultracold plasma. We present coupled rate-equation simulations that model the underlying kinetic processes and molecular dissociation channels in both a uniformly distributed plasma and under the conditions dictated by our experimental geometry. Simulations predict a fast electron-driven collisional avalanche to plasma followed by slow electron-ion recombination. Within 20 μs, release of Rydberg binding energy raises the electron temperature of a static plasma to Te=100 K. Providing for a quasi-self-similar expansion, the hot electron gas drives ion radial motion, reducing Te. These simulations provide a classical baseline model from which to consider quantum effects in the evolution of charge gradients and ambipolar forces in an experimental system undergoing responsive avalanche dynamics.
中文翻译:
Rydberg气体高斯椭球的速率方程耦合水动力模拟:经典雪崩及其向分子等离子体的演化
超声分子束中夹带的椭球体积的里德伯格分子在纳秒级的时间尺度上演化形成强耦合的超冷等离子体。我们提出了耦合速率方程模拟,该模拟模拟了均匀分布的等离子体中以及在我们的实验几何形状所规定的条件下的基本动力学过程和分子解离通道。模拟预测到等离子体的快速电子驱动碰撞雪崩,然后缓慢的电子离子重组。20μ以内s,释放里德堡结合能将静态等离子体的电子温度提高到T e = 100K.由于提供了准自相似的膨胀,热电子气驱动离子径向运动,从而降低了T e。这些模拟提供了一个经典的基线模型,从中可以考虑在经历响应雪崩动力学的实验系统中,电荷梯度和双极性力的演化中的量子效应。