Journal of Physical Chemistry A, Vol.101, No.14, 2634-2642, 1997
Infrared-Emission from the Cf3+no2 Reaction
The reaction of the CF3 radical with NO2 has been investigated by using time-resolved FTIR emission spectroscopy. Strong infrared emission has 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, Delta 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 was measured to be (2.4 +/- 0.5) x 10(-11) cm(3) molecule(-1) s(-1). The F atom formation pathway Ib is the minor channel : the relative branching ratio of reactions la and Ib was estimated as 1 : 0.015. The formation of the FON isomer formed via a five-center intermediate is discussed 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 observed, with proportionally less vibrational excitation in the CF2O product.
Keywords:ABSOLUTE RATE CONSTANTS;ATOM-RADICAL KINETICS;CF3O RADICALS;SPECTROSCOPIC EVIDENCE;NITROSYL FLUORIDE;NO;THERMOCHEMISTRY;PHOTOOXIDATION;DISSOCIATION;OXIDATION