Kinetics of the Reaction D+H2=HD+H

The reaction D+H2=HD+H has been studied in the gas phase in the temperature range 274° to 468°K. By attributing the curvature in the Arrhenius plot to quantum-mechanical tunneling and interpreting the results in terms of absolute reaction rate theory the rate constant was given by the expression k3=3.63×1015T−12Γexp(−9.40×103/RT). The results obtained previously for the reaction H+p-H2=o-H2+H fitted the equation k1=1.18×1015T−12Γ exp(−9.21×103/RT). The tunneling factors Γ were calculated on the assumption of a truncated parabolic barrier and gave almost identical values for the force constant of the asymmetric stretching vibration of the complex. The results are compared with recent theoretical calculations.