Gas phase studies of Na diffusion in He and Ar and kinetics of Na+Cl2 and Na+SF6

A fast flow reactor, using an oven source and resonant fluorescence detection, was built to study the kinetics of sodium atoms in the gas phase. The rate coefficients for Na+Cl2 and Na+SF6 are (7.80±1.6)×10−10 and (1.17±0.2)×10−12 cm3 molecule−1 s−1, respectively. Since collisions with the wall remove sodium with approximately unit efficiency, gaseous diffusion coefficients of sodium in the carrier gas can be measured. DNa,He=325±33 cm2 Torr s−1 at 290 K and DNa,Ar=140±14 cm2 Torr s−1 at 281 K. The experimental results are compared with previous studies and simple theoretical models.