R.: Rate coefficients for reactions of hydroxyl radicals with methane and deuterated methanes

as well as that of OD with CH4 (k6) have been measured using the pulsed photolytic production of OH followed by its detection via pulsed laser induced fluorescence. k1-k4 and k6 were measured between 220 and 415 K, while k5 was measured down to 195 K. The measured rate coefficients do not strictly obey the Arrhenius expression. However, below 298 K, they can be represented by the expressions (in cm3 molecule-1 s-1): k1) (3.11 ( 0.44) 10-12 exp[-(1910 ( 70)/T]; k2) (2.3 ( 1.2) 10-12 exp[-(1930 ( 250)/T]; k3) (1.46 ( 0.22) 10-12 exp[-(1970 ( 70)/T]; k4) (1.00 ( 0.22) 10-12 exp[-(2100 ( 120)/T]; k5