CHEMILUMINESCENCE FROM REACTION OF THE GROUP IIIA METALS WITH HALOGEN MOLECULES

We observe chemiluminescence from the following reactions for various combinations of the group IIIa (aluminum, gallium and indium) metals and halogen.;M + 2Cl(,2) MCl(,2)(' )+ 2Cl.;M(,2) + F(,2) M(,2)F* + F.;The emission from the monofluoride have been observed under single collision conditions at collision energies up to 24 kcal mole('-1). Relative rates of formation of the product vibronic states have been extracted from several spectra to reveal vibrational population inversion and near statistical electronic branching ratios. Increased reactant translational energy goes preferentially to product translational and rotational energy. All of the observations are consistent with reaction to form electronically excited products proceeding by a direct, non-adiabatic mechanism with mixed energy release.;M + F(,2) MF*(('3)(PI)) + F.;We have also observed the monofluoride emission on the addition of pressures of SF(,6) in the millitorr range. At these pressures, we observe the quenching of the vibrational state distribution due to the energy transfer to the SF(,6). The lack of knowledge about several important experimental parameters keeps us from determining the exact processes occurring during the collision.;We observe emission of GaCl(,2) due to reaction of Ga with 2 Cl(,2) molecules probably due to the reaction sequence.;Ga + Cl(,2) GaCl('(DAG)) + Cl.;GaCl('(DAG)) + Cl(,2) GaCl(,2) + Cl.;Our data allow us to make a lower bound estimate of the ClGa-Cl bond strength of 136 kcal mole('-1). We make estimates of the relative rates of radiative recombination processes which suggest that the two-step mechanism will be the dominant mechanism for a number of reports of emission from electronically excited MX(,2) species.;Emission from molecules of the type M(,2)F has been observed from reaction of the metal dimer with F(,2). The emission extends from approximately 400 nm to over 750 nm. Two broad structureless features are observed which we associate with emission from two bound excited states. A lower bound of 100 kcal mole('-1) can be placed on the bond strength of the M(,2)-F bond in the ground state of M(,2)F, which may be unstable with respect to MF + F.