Diffusion coefficients for Br2 in NO and Br in Ar at 298 °K

A two-step laser photodissociation technique was used to generate Br atoms in NO or Ar mixtures. Time resolved mass spectrometric detection of Br2, formed by fast homogeneous recombination in the NO mixtures, or by a heterogeneous wall reaction in the Ar mixtures, led to a determination of diffusion coefficients for Br2 in NO and for Br in Ar at 298 °K. The reported values are DBr2−NO = (0.11±0.01) cm2/sec and DBr–Ar= (0.21±0.04) cm2/sec at 1 atm. General solutions to the diffusion and heterogeneous reaction equations for the geometry of this experiment are presented.