Alkali-Halide Chemiluminescence: Studies on the Fluctuation Bands from some Alkali (Li, Na, K)-Halogen (CI, Br, I)-Reactions

Molecular chemiluminescence spectra from selected alkali-halogen reactions are presented using a beam-gas arrangement operating with pressures between 10 -1 mtorr (single collision conditions) up to 10 mtorr in the reaction zone. Spectra are presented for the chemiluminescent reactions M2 + X 2 > M X * + MX, where M2 = K 2 , Na2 and X 2 = C12, Br2 ,12 . The MX* emitter is identified by comparison with previous absorption and emission studies of these molecules. The sodium reaction with I2 as well as all lithium reactions with different halogens (CI2, Br2,12) do not yield appreciable molecular emission. The differences in molecular chemiluminescence intensities among this type of reactions can be understood in terms of the Landau-Zener formalism for an electron jump and turn out to be consistent with the results from measurements on absorption, emission and dissociation.