Reaction dynamics of Si ( P J 3 ) + O 2 → Si O ( X Σ + 1 ) + O studied by a crossed-beam laser-induced fluorescence techniqueDynamics of the reaction, AlϩO 2 →AlOϩO, was studied by using the crossed-beam technique at five collision energies from 6.9 to 25.3 kJ/mol. The Al atomic beam was generated by laser vaporization and crossed with the O 2 beam at a right angle. The product AlO was detected by laser-induced fluorescence of the AlO(B 2 ⌺ ϩ -X 2 ⌺ ϩ ) transition and the rotational-vibrational distributions were determined. The observed rotational and vibrational distributions displayed greater populations in lower vibrational and rotational levels than expected statistically. Rotational distributions were also determined for two spin-orbit states of Al, Al( 2 P 1/2 ) and Al( 2 P 3/2 ), at two collision energies. At a collision energy of 12.2 kJ/mol, the higher energy spin-orbit excited state, Al( 2 P 3/2 ), showed lower reactivity, i.e., about one-third of the ground spin-orbit state, Al( 2 P 1/2 ). However, the rotational distributions for the two states were almost identical. Both the reactivity and rotational distributions for Al( 2 P 1/2 ) and Al( 2 P 3/2 ) became similar at a higher collision energy, 18.5 kJ/mol. These results suggest that the reaction of Al with O 2 proceeds via an intermediate complex.Both spin-orbit states lead to the complex, lose memory of the initial electronic state, and provide identical rotational distributions.