Study of the chemiluminescent reaction between alkali dimers and oxygen atoms

The reaction of alkali dimers with oxygen atoms has been studied in a crossed beam experiment. Strong chemiluminescence of the reaction products was observed. It is shown that the luminescence was emitted by alkali atoms from the reaction M2+O→MO+M (M alkali atom). M can be excited up to the exoergicity of this reaction at least in the cases M = Cs and Na. For M = Cs, detailed rate constants for the excitation of the different excited states have been determined using both laser induced fluorescence and chemiluminescence. The rates decrease nearly exponentially as a function of the excitation energy. They partly follow the expectation of statistical theories. Absolute reaction cross sections have been determined for all of the reactions investigated. They agree partially with those predicted by the harpoon model.