Gijsbertsen A, Linnartz H, Rus G, Wiskerke A E, Stolte S, Chandler D W, Kłos J
Laser Centre and Department of Physical Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
J Chem Phys. 2005 Dec 8;123(22):224305. doi: 10.1063/1.2126969.
The first measurements of differential inelastic collision cross sections of fully state-selected NO (j=12, Omega=12, epsilon= -1) with He are presented. Full state selection is achieved by a 2 m long hexapole, which allows for a systematic study of the effect of parity conservation and breaking on the differential cross section. The collisionally excited NO molecules are detected using a resonant (1+1') REMPI ionization scheme in combination with the velocity-mapped, ion-imaging technique. The current experimental configuration minimizes the contribution of noncolliding NO molecules in other rotational states j, Omega, epsilon--that contaminates images--and allows for study of the collision process at an unprecedented level of detail. A simple method to correct ion images for collision-induced alignment is presented as well and its performance is demonstrated. The present results show a significant difference between differential cross sections for scattering into the upper and lower component of the Lambda-doublet of NO. This result cannot be due to the energy splitting between these components.
首次给出了全态选择的一氧化氮（j = 12，Ω = 12，ε = -1）与氦的微分非弹性碰撞截面的测量结果。通过一个2米长的六极杆实现全态选择，这使得能够系统地研究宇称守恒和宇称破缺对微分截面的影响。碰撞激发的一氧化氮分子通过共振（1 + 1'）多光子电离（REMPI）方案结合速度映射离子成像技术进行检测。当前的实验配置将处于其他转动状态j、Ω、ε的非碰撞一氧化氮分子（这些分子会污染图像）的贡献降至最低，并允许以前所未有的详细程度研究碰撞过程。还提出了一种校正碰撞诱导取向的离子图像的简单方法，并展示了其性能。目前的结果表明，散射到一氧化氮的Λ双重态的上、下分量的微分截面之间存在显著差异。这一结果不可能是由于这些分量之间的能量分裂所致。
