Chemiluminescence studies. IV. Pressure-dependent photon yields for Ba, Sm, and Eu reactions with N2O, O3, O2, F2, and NF3

Chemiluminescence spectra and photon yields are presented for reactions of Ba, Sm, and Eu with N2O, O3, O2, F22, and NF3 for the pressure range 0.5 to 20 torr. Peak yields range from 2.5 percent to 70 percent, with the reactions of Sm with NF3 and F2 having the highest yields. These latter reactions put from 12 percent to 16 percent of their available thermal energy into luminous output. The pressure dependence of the photon yields deduced from these and other recent measurements suggests that the initial exothermic reaction primarily populates high vibrational levels of the ground electronic state of the newly formed diatomic. Radiating states would then be populated mainly by collision-induced vibrational-to-electronic internal conversion