The chlorine atom recombination reactions in the buffer gases of chlorine, argon, nitrogen, and carbon dioxide below 1 atm pressure were studied by the laser photolysis/chemiluminescence detection technique. The vibrationally resolved transient chemiluminescence spectra were recorded. A reaction mechanism which included recombinations, electronic quenching, and vibrational energy relaxation processes of both the A and B excited states of the chlorine molecules was proposed to account for the present experimental observations and also the related experimental results reported in the literature. Under the approximation of the exponential energy-gap rate laws for the rate constants of the inter-and intraelectronic vibrational energy relaxations as proposed in the literature, either the rate constants of electronic quenching, vibrational relaxation within the same electronic states, and interelectronic vibrational energy transfer between the A and B states of the chlorine molecules by the buffer gases were determined or their upperbound values were estimated. The long-time steady state behavior of the mechanism was also analyzed analytically and numerically.