Theoretical and experimental investigation of the Knudsen layer produced by intensive evaporation of iodine

This paper investigates the kinetic boundary layer (Knudsen layer) adjacent to the surface of evaporating iodine, both experimentally and theoretically. By means of fluorescence spectroscopy with a tunable dye laser the translational and rotational temperature, the density, and the macroscopic flow velocity have been measured. The experimental results are compared with theoretical calculations. An approximate solution of the Boltzmann equation has been obtained by means of the four-moment method and the model of Maxwellian molecules