Electronic branching ratios in chemiluminescence from the collisions of Ca∗(3PJ, 1D2) atoms with halogenated methanes CX4−nYn (X, Y=F, Cl, Br)

Chemiluminescent reactions of calcium in the metastable 3PJ and 1D2 states with CFCl3, CFBr3, CCl2Br2, CCl3Br, and CFClBr2 molecules were studied in a beam–gas arrangement. CaCl and CaBr spectra associated with the A 2Π–X 2Σ+ and B 2Σ+–X 2Σ+ transitions were observed, while analogous emission from CaF was absent. The total collision cross-sections, chemiluminescence cross-sections and photon yields were measured. The photon yields are in a good agreement with statistical distribution based on information theory approach when the CX3 product is treated as a nonlinear rotor without vibrational excitation.