Ion imaging studies of product rotational alignment in collisions of NO ð X 2 P 1 = 2 ; j 1⁄4 0 : 5 Þ with Ar

The collision-induced rotational alignment of NO ðXP1=2; v 1⁄4 0; j 1⁄4 4:5, 8.5, 11.5, 12.5, and 15.5) is measured for rotationally inelastic scattering of NO ðXP1=2; v 1⁄4 0; j 1⁄4 0:5Þ with Ar at 520± 70 cm 1 of center-of-mass collision energy. The experiments are performed by velocity-mapped ion imaging with polarized 1þ 10 REMPI of the scattered NO product. Differential cross-sections (DCSs), corrected for alignment effects, are also reported. While the alignment correction is important, it does not change the positions of the observed rotational rainbows. The alignment moments and DCSs are compared with calculations using Alexander s CCSD(T) PESs. The theoretical and experimental DCSs show excellent agreement, as do the theoretical and experimental alignment moments for low Dj. For high Dj collisions and back-scattered trajectories, which sample the hard wall of the PES, the theoretical and experimental alignment moments show less agreement. 2004 Elsevier B.V. All rights reserved.