Diffusion of Br₂ Molecules in KBr

Abstract

The penetration depth of Br₂ into KBr crystal is measured in the temperature range from 375°C to 600°C using OH⁻ center as an indicator. The plot of the inverse square of the penetration depth against the inverse pressure of bromine leads to a linear relation indicating that the bromine diffuses in the form of diatomic Br₂ molecule. The intercept and the slope of the linear plot permit the evaluation of diffusion coefficient and Henry’s constant of Br₂ in KBr: D=0.17exp(−0.95⁄kT) cm²sec⁻¹ and K=7.1×10¹⁷exp(−0.43⁄kT) cm⁻³Torr⁻¹ respectively.