The reaction O+(NO)2was studied by use of a crossedhyphen;beam apparatus. An (NO)2beam generated by the supersonic expansion crossed at right angles with a collimated effusive beam containing oxygen atoms which were formed by microwave discharge. The product NO@B2was detected by the chemiluminescence. The angular distribution of the product was measured by an anglehyphen;resolved emission detection technique. The distribution has forward and backward peaks with respect to the oxygen atom incidence and indicates the occurrence of an intermediate complex in the course of the reaction. The angular velocity distribution, as well as the onset of the chemiluminescence, indicates that the reaction exothermicity appears mostly as internal energy of NOast;2. The remaining energy flows into the product translation and rotation; the vibrational freedom of the thirdhyphen;body molecule is not effective as an energy absorber. The emission intensity was found to decrease with increasing relative collision energy. A sharp drop of the intensity was observed at 2 kcal/mol of collision energy, which is in good agreement with the bond energy of the NO dimer.
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