Direct rate measurements on the reaction D + OH → OD + H from 300 to 515 K

Abstract

Rate constants for the reaction D + OH → OD + H (1), have been measured at temperatures from 300 to 515 K. The pseudo-first-order decay of OH radicals, generated by pulsed laser photolysis of HNO₃ or H₂O, was monitored by resonance fluorescence in the presence of a known excess concentration of D atoms produced by microwave discharge in the flowing gas mixture. The expression k₁=(1.9 ± 0.3)× 10^–9T^{–(0.63 ± 0.05)} cm³ molecule^–1 s^–1, fitted the observed rate constants, yielding a value at 298 K (k₁= 5.3 × 10^–11 cm³ molecule^–1 s^–1) which is only 40% of the only other determination of this rate constant at room temperature.