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 within the equilibrium pressure range between 10ͨtwo;9 and 10ͨtwo;4 Pa at surface temperatures of six.five and 4.two K. The mean residence times of H2 on copper were obtained from the observation of the time development of the surface density in a very transitional state approaching equilibrium, and are 50–500 s for the coverage between one and 0.18 at four.two K of the substrate temperature. The adsorption energies of 1.eighteen–one.twenty seven kJ/mol, and therefore the condensation coefficient of zero.074̵one;zero.018 were also deduced.