The electronic properties and dissociative channels of the alternative to the CCl 2 F 2 (CFC-12) refrigerant, 1,1,1,2-tetrafluoroethane (HFC-134a) with a low global warming potential (GWP, 1430), were revealed by computational chemistry. The results show that CF 3 + and CHF 2 + ions are mainly produced by ionization. The CF 3 CH 2 + ion is produced by ion pair formation and by direct ionization in the energy region higher than approximately 15 eV, but also in small amounts by the ionization of the dissociated CF 3 CH 2 radical. This information is useful for etching process engineers in leading-edge semiconductor manufacturing.