PROJECT TITLE :

Application of electron stimulated desorption techniques to measure the isotherm and the mean residence time of hydrogen physisorbed on a metal surface

ABSTRACT:

Electron stimulated desorption techniques were applied to probe the density of H2 physisorbed on a cold surface. The adsorption isotherm of H2 on a copper surface was measured in the equilibrium pressure range between 10−9 and 10−4 Pa at surface temperatures of 6.5 and 4.2 K. The mean residence times of H2 on copper were obtained from the observation of the time development of the surface density in a transitional state approaching equilibrium, and are 50–500 s for the coverage between 1 and 0.18 at 4.2 K of the substrate temperature. The adsorption energies of 1.18–1.27 kJ/mol, and the condensation coefficient of 0.074–0.018 were also deduced.