Brouard M, Gordon S D S, Hackett Boyle A, Heid C G, Nichols B, Walpole V, Aoiz F J, Stolte S
The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom.
Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
J Chem Phys. 2017 Jan 7;146(1):014302. doi: 10.1063/1.4972565.
The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging. Experimental integral steric asymmetries are presented for NO(X) + Ar, for both spin-orbit manifolds, and Kr, for the spin-orbit conserving manifold. The integral steric asymmetry for spin-orbit conserving and changing transitions of the NO(X) + O system is also presented. Close-coupled quantum mechanical scattering calculations employing well-tested ab initio potential energy surfaces were able to reproduce the steric asymmetry observed for the NO-rare gas systems. Quantum mechanical scattering and quasi-classical trajectory calculations were further used to help interpret the integral steric asymmetry for NO + O. Whilst the main features of the integral steric asymmetry of NO with the rare gases are also observed for the O collision partner, some subtle differences provide insight into the form of the underlying potentials for the more complex system.
使用交叉分子束装置记录了多种碰撞伙伴与NO(X)发生非弹性散射时的积分空间不对称性。在NO键轴在静电场中取向之前，利用六极电场选择NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f)分子的初始状态，从而能够探测碰撞伙伴在分子的N端或O端的散射情况。利用(1 + 1')共振增强多光子电离结合速度映射离子成像技术对散射的NO分子进行状态选择性探测。给出了NO(X) + Ar在两个自旋轨道分支以及NO(X) + Kr在自旋轨道守恒分支的实验积分空间不对称性。还给出了NO(X) + O系统自旋轨道守恒和变化跃迁的积分空间不对称性。采用经过充分测试的从头算势能面进行的紧密耦合量子力学散射计算能够重现NO - 稀有气体系统中观察到的空间不对称性。进一步利用量子力学散射和准经典轨迹计算来帮助解释NO + O的积分空间不对称性。虽然对于O碰撞伙伴也观察到了NO与稀有气体积分空间不对称性的主要特征，但一些细微差异为更复杂系统的潜在势能形式提供了见解。
