Ion imaging measurement of collision-induced rotational alignment in Ar-NOscattering

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 b y velocity-mapped ion imaging with polarized 1+1' REMPI probing of the scat tered NO products. It is shown that the azimuthal information intrinsic to imaging detection allows the measurement of additional alignment moments no t previously reported. The measured alignment shows only qualitative agreem ent with the predictions of the kinematic apse conservation model. (C) 2001 American Institute of Physics.