Scattering resonances in slow NH3-He collisions.
Scattering resonances in slow NH3-He collisions.
复制标题
NH3-He 缓慢碰撞中的散射共振。
DOI：
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发表时间：
2011
影响因子：
4.4
通讯作者：
A. van der Avoird
中科院分区：
文献类型：
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作者：
K. B. Gubbels;S. V. D. van de Meerakker;G. Groenenboom;G. Meijer;A. van der Avoird
我们从理论上研究 NH(3) 分子与 He 原子的缓慢碰撞，其中我们特别关注散射共振的观察。我们使用完全收敛的量子紧耦合计算，计算碰撞能量范围从 10(-4) cm(-1) 到 130 cm(-1) 的状态到状态积分和微分截面。为了描述 NH(3) 分子和 He 原子之间的相互作用，我们提出了一个基于 4180 个从头开始点的精确拟合的四维势能表面。在碰撞之前，我们认为氨分子处于反对称伞态，角动量 j = 1 且投影 k = 1，这是斯塔克减速的合适状态。我们发现了明显的形状和费什巴赫共振，特别是对于 j = k = 1 的对称伞态的非弹性碰撞。我们通过观察散射波函数、相移和寿命来详细分析观察到的共振结构。最后，我们讨论了在未来使用 Stark 减速 NH(3) 光束的交叉分子束实验中观察预测的散射共振的前景。
We theoretically study slow collisions of NH(3) molecules with He atoms, where we focus in particular on the observation of scattering resonances. We calculate state-to-state integral and differential cross sections for collision energies ranging from 10(-4) cm(-1) to 130 cm(-1), using fully converged quantum close-coupling calculations. To describe the interaction between the NH(3) molecules and the He atoms, we present a four-dimensional potential energy surface, based on an accurate fit of 4180 ab initio points. Prior to collision, we consider the ammonia molecules to be in their antisymmetric umbrella state with angular momentum j = 1 and projection k = 1, which is a suitable state for Stark deceleration. We find pronounced shape and Feshbach resonances, especially for inelastic collisions into the symmetric umbrella state with j = k = 1. We analyze the observed resonant structures in detail by looking at scattering wavefunctions, phase shifts, and lifetimes. Finally, we discuss the prospects for observing the predicted scattering resonances in future crossed molecular beam experiments with a Stark-decelerated NH(3) beam.