Experimental determination of desorption rates and of heats of desorption

Gas discharge rates through a de Laval nozzle from a closed chamber have been measured for Ar, He, and CO_2. The effective desorption rates from vessels containing sand and silica gel have also been determined at various temperatures by measuring the time rate of pressure decay in the chamber. The experimental data have been used, in conjunction with a theoretical expression for diffusion controlled desorption rates, to estimate heats of desorption from silica gel. Results have been obtained that are in approximate agreement with estimates made by other investigators using more conventional procedures.