RATE-CONSTANT FOR THE REACTION CH3-TILDE(3)B(1)) AT 298 K(CH2((X)OVER)

The rate constant for the reaction between CH3 and CH2 ((X) over tilde (3)B(1), = (CH2)-C-3) radicals, CH3+(CH2)-C-3 --> products, was determ ined at T = 298 K and p = 1.33 mbar in an isothermal discharge flow re actor. Far Infrared Laser Magnetic Resonance (FIR-LMR) was employed fo r monitoring (CH2)-C-3 and CH3 radical concentration-versus-time profi les. CH3 was determined in the form of NO via the conversion reaction CH3+NO2 --> CH3O+NO. The CH3 and (CH2)-C-3 radicals were generated by the reactions F+CH4 --> CH3+HF and F+CH3 --> (CH2)-C-3+HF. The rate co nstant for the recombination reaction CH3+CH3+M --> C2H6+M was determi ned together with the rate constant for reaction (1). The measurements gave a rate constant value for reaction (1) of k(1)=(6.5+/-1.2).10(13 ) cm(3)/mol s.