State-to-state differential cross sections have been measured for scattering of NO((2) Pi(1/2)j=0.5), Ar at kinetic energies of 117, 149, 442, and 1694 cm(-1). The differential cross sections at each collision energy are presented as a function of final state (Omega’,j’) at constant center-of-mass scattering angle. Center-of-mass angular distributions are also given for final rotational states ((2) Pi(1/2), j’ = 1.5, 2.5, 8.5, 12.5, and 14.5) at a kinetic energy of 442 cm(-1), and for J’ = 18.5 at a kinetic energy of 1694 cm(-1). Rotational rainbow structure is seen in both types of data. The results are generally in good agreement with quantum scattering calculations carried out by Alexander [J. Chem. Phys. 99, 7725 (1993)] using newly calculated ab initio potential energy surfaces, and thus may serve as a new benchmark for the microscopic dynamics of molecular energy transfer in open-shell molecules.