The product gas yields for a 30 mTorrC2H213.56 MHz glow discharge were measured using mass spectrometry. The volatile products areH2,C4H2,andC6H2.A reaction mechanism has been proposed that accounts quantitatively for the yields ofC4H2andC6H2,and film deposition rate, as a function of discharge power. The product gasesC4H2andC6H2are depleted at high rates in the plasma by electron collisional dissociation, and by reaction with H atoms andC2Hradicals. Under high power conditions suitable for diamondlike carbon deposition it is proposed that the film growth is dominated by the radicalsC4H3,C6H3,andC2H.These results are compared with the kinetics of methane rf glow discharges under similar conditions. ©1997 American Institute of Physics.