INFRARED-EMISSION FROM THE CF3+NO2 REACTION

The reaction of the CF3 radical with NO2 has been investigated by usin g time-resolved FTIR emission spectroscopy. Strong infrared emission h as been attributed to products, CF2O and FNO, excited in the nu(2) and nu(1) modes, respectively. The direct one-step production pathway la is suggested as a major reaction channel: CF3 + NO2 --> CF2O + FNO, De lta H degrees(298) = -267 kJ mol(-1) (1a); --> CF2O + F + NO, Delta H degrees(298) = -31 kJ mol(-1) (Ib). The rate constant for reaction 1 w as measured to be (2.4 +/- 0.5) x 10(-11) cm(3) molecule(-1) s(-1). Th e F atom formation pathway Ib is the minor channel: the relative branc hing ratio of reactions la and Ib was estimated as 1 : 0.015. The form ation of the FON isomer formed via a five-center intermediate is discu ssed as a possible carrier of an unidentified emission band near 1880 cm(-1). The CF3O + NO reaction was investigated by the same technique. Lower emission intensities from the same reaction products were obser ved, with proportionally less vibrational excitation in the CF2O produ ct.