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Chemiluminescent reactions of ground state (Ca, Sr, and Ba) atoms with (Cl 2 , Br 2 , I 2 , ICl, and IBr) were studied in a beam-gas arrangement. The MX 2 * pseudo-continua were measured as a function of target gas pressure in the 0.0001-0.25 Pa range. To identify the main reaction channels that contribute to MX 2 * formation and to obtain their relative contributions, kinetic models were fitted to the data. The following channels were considered: (1) radiative two-body recombination (R2BR), (2) radiative three-body recombination (R3BR), (3) two consecutive harpooning steps involving MX † intermediate (two-step chemiluminescent reaction TSCR), and (4) combinations of the above. On their own, none of the mechanisms (1-3) provide satisfactory data fits. The best agreement is obtained by a model involving both R2BR and TSCR. The branching ratios of these channels were determined for p ) 0-0.25 Pa. At 0.16 Pa these R2BR fractions vary from 7% (for Ca, Sr + ICl) to 79% (for Ba + IBr). Absolute CL cross sections and lower limits of photon yields were estimated by cross-calibrations. Photon yields for R2BR varied from 0.0004% to 0.037%, depending on the collision partners.