The interaction of deuterium with polycrystalline molybdenum at 80 K i
n the exposure range of 20-600 L, was studied by thermal desoption spe
ctroscopy and work function measurements. Evidence of molecular and di
ssociative adsorption was found. Desorption peak shapes suggest the pr
esence of a distribution of interacting adsorption sites with differen
t adsorption energies.