Kinetics of the C-2(a(3)Pi(u)) radical reacting with selected molecules and atoms

Rate coefficients for reactions of the C-2 radical in its a(3)Pi(u) electro nic state with H, N and O atoms and with C3O2, C4F6, H-2, NO, N2O, C2H2, C2 H4, C3H4 and C6H6 were determined. This work represents the first study of reactions of C-2(a(3)Pi(u)) radical s with the atoms investigated at room temperature and 4 Torr: total pressur e. The bimolecular rate constants obtained for the atom reactions were k(C2 +O) = (9.8 +/- 1.0) x 10(-11), k(C2+N) = (2.8 +/- 1.0) x 10(-11) and k(C2+N ) < 6 x 10(-14), in units of cm(3) s(-1). In addition, the reaction C-2 + O was found to be independent of total pressure in the range 2-60 Torr. For the reaction C-2(a(3)Pi(u)) + ethene (C2H4) a temperature and pressure independent rate constant of (9.5 +/- 1.2) x 10(-11) cm(3) s(-1) was obtain ed in the temperature range 298-1000 K at 100 Torr total pressure and in th e pressure range 5-100 Torr at 298 K. The following rate constants were det ermined at room temperature and a total pressure of 4 Torr for the reaction s of C-2(a(3)Pi(u)) radicals with benzene (C6H6), acetylene (C2H2) and alle ne (C3H4): k(C2+C6H6) = (4.9 +/- 0.1) x 10(-10), k(C2+C2H2) = (1.0 +/- 0.1) x 10(-10) and k(C2+C3H4) = (1.9 +/- 0.3) x 10(-10), in units of cm(3) s(-1 ). The reaction C-2 + NO was investigated at room temperature and 100 Torr tot al pressure, a rate constant k(C2+NO) = (6.8 +/- 0.3) x 10(-11) cm(3) s(-1) was obtained. The reaction C-2 + N2O was studied at 4 Torr total pressure in the temperature range 300-700 K for which a temperature independent rate constant k(C2+N2O) = (3.1 +/- 0.4) x 10(-14) cm(3) s(-1) was determined.