Ion imaging measurement of collision-induced rotational alignment in Ar-NO scattering

Collision-induced rotational alignment of NO X(2)Pi (1/2)(upsilon =0, j=8.5) is measured for rotationally inelastic scattering of NO X(2)Pi (1/2)(v=0, j=0.5) with Ar at 65 meV collision energy. The experiments are performed by velocity-mapped ion imaging with polarized 1+1' REMPI probing of the scattered NO products. It is shown that the azimuthal information intrinsic to imaging detection allows the measurement of additional alignment moments not previously reported. The measured alignment shows only qualitative agreement with the predictions of the kinematic apse conservation model. (C) 2001 American Institute of Physics.