Leng Joseph G, Sharples Thomas R, McKendrick Kenneth G, Costen Matthew L
Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
Phys Chem Chem Phys. 2022 Mar 16;24(11):6525-6534. doi: 10.1039/d1cp05960b.
A crossed molecular beam, velocity-map ion imaging apparatus has been used to determine differential cross sections (DCSs) and angle-resolved rotational angular momentum alignment moments for the state-resolved rotationally inelastic scattering of NO(Σ, = 0, = 0.5 ) with Kr at an average collision energy of 785 cm. The experimental results are compared to close-coupled quantum scattering (QS) calculations performed on a literature potential energy surface (J. Kłos , , 2008, , 244303). DCSs are very strongly forward scattered, with weaker side and backward scattered peaks becoming progressively more important at higher-'. Good agreement is found between experimental and QS DCSs, indicating that the PES is an accurate reflection of the NO()-Kr interaction energies. Partial wave analysis of the QS DCSs isolates multiple scattering mechanisms contributing to the DCSs, including L-type rainbows and Fraunhofer diffraction. Measured alignment moments are not well described by a hard-shell kinematic apse scattering model, showing deviations in the forward scattering hemisphere that are in agreement with QS calculations and arise from attractive regions of the PES. These discrepancies emphasise that established scattering mechanisms for molecules such as NO with lighter noble gases cannot be extrapolated safely to heavier, more polarisable members of the series.
一台交叉分子束速度成像离子成像装置被用于确定在平均碰撞能量为785厘米的情况下，NO（Σ，J = 0，Ω = 0.5）与Kr的态分辨转动非弹性散射的微分截面（DCS）和角分辨转动角动量取向矩。实验结果与在文献势能面上进行的密耦量子散射（QS）计算进行了比较（J. Kłos等人，2008年，244303）。DCS非常强烈地向前散射，较弱的侧向和向后散射峰在更高的J时变得越来越重要。实验和QS DCS之间发现了很好的一致性，表明该势能面准确反映了NO（J）-Kr相互作用能。对QS DCS的分波分析分离出了对DCS有贡献的多种散射机制，包括L型彩虹和夫琅禾费衍射。硬壳运动学拱点散射模型不能很好地描述测量到的取向矩，在前向散射半球显示出与QS计算一致的偏差，这些偏差源于势能面的吸引区域。这些差异强调，对于NO等分子与较轻惰性气体的既定散射机制，不能安全地外推到该系列中较重、极化率更高的成员。
