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

Abstract

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. D_Na,He=325±33 cm² Torr s⁻¹ at 290 K and D_Na,Ar=140±14 cm² Torr s⁻¹ at 281 K. The experimental results are compared with previous studies and simple theoretical models.