Zastrow Alexander von, Onvlee Jolijn, Parker David H, van de Meerakker Sebastiaan Y T
Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, Nijmegen, 6525 AJ Netherlands.
EPJ Tech Instrum. 2015;2(1):11. doi: 10.1140/epjti/s40485-015-0020-z. Epub 2015 Jul 28.
A Stark decelerator produces beams of molecules with high quantum state purity, and small spatial, temporal and velocity spreads. These tamed molecular beams are ideally suited for high-resolution crossed beam scattering experiments. When velocity map imaging is used, the Stark decelerator allows the measurement of scattering images with unprecedented radial sharpness and angular resolution. Differential cross sections must be extracted from these high-resolution images with extreme care, however. Common image analysis techniques that are used throughout in crossed beam experiments can result in systematic errors, in particular in the determination of collision energy, and the allocation of scattering angles to observed peaks in the angular scattering distribution. Using a high-resolution data set on inelastic collisions of velocity-controlled NO radicals with Ne atoms, we describe the challenges met by the high resolution, and present methods to mitigate or overcome them. 34.50.-s; 37.10.Mn.
斯塔克减速器能产生具有高量子态纯度、且空间、时间和速度展宽都很小的分子束。这些经过“驯服”的分子束非常适合用于高分辨率的交叉束散射实验。当使用速度成像技术时，斯塔克减速器能够以前所未有的径向清晰度和角分辨率测量散射图像。然而，必须极其小心地从这些高分辨率图像中提取微分截面。在交叉束实验中普遍使用的常规图像分析技术可能会导致系统误差，尤其是在碰撞能量的确定以及将散射角分配给角散射分布中观测到的峰时。通过使用关于速度可控的一氧化氮自由基与氖原子非弹性碰撞的高分辨率数据集，我们描述了高分辨率所面临的挑战，并提出了减轻或克服这些挑战的方法。34.50.-s；37.10.Mn。
