Collision Energy Dependent Cross Section and Rotational Alignment of NO (A 2Σ+) in the Energy-Transfer Reaction of N2 (A3Σu+ ) + NO (X 2Π) → N2 (X 1Σg+) + NO (A 2Σ+)

We have studied the collision energy dependent cross section and alignment of NO (A (2)Sigma(+)) rotation in the energy-transfer reaction of N2 (A (3)Sigma(+)) + NO (X (II)-I-2) -> (2)(N) (X (1)Sigma(+)(g)) + NO (A (2)Sigma(+)) at the collision energy (E) region of 0.03-0.2 eV. NO (A (2)Sigma(+)) emission in two linear polarization directions in the collision frame (parallel (parallel to) and perpendicular (perpendicular to) with respect to the relative velocity vector (v(R))) has been measured as a function of collision energy. NO (A (2)Sigma(+)) rotation (J-vector) turns out to be aligned perpendicular to v(R). In addition, collision energy is found to enhance the degree of alignment of NO (A (2)Sigma(+)) rotation. The collision energy dependent cross sections sigma (parallel to(perpendicular to))(E) (excitation functions) show a rapid fall-off following an initial rise with a threshold less than 0.02 eV. The excitation function at the parallel alignment of NO (A (2)Sigma(+)) rotation, s(J parallel to v(R), (E), is slightly shifted to the low collision energy region as compared with sigma(J perpendicular to v(R), E). We propose that the rapid fall-off feature in the excitation function is attributed to the multidimensional nonadiabatic transitions.