Stay time measurements for Xe, Kr, and CO2 physisorbing on Ni and Cu surfaces

摘要: Abstract A pulsed molecular beam apparatus is used to measure mean stay times for gases physisorbing on cooled surfaces. Most of the data are Xe nickel Data also presented Kr and CO 2 nickel, copper, ion-sputter-cleaned nickel. All targets polycrystalline. Surface temperatures range from 92 125 K measured 10 −5 −3 s. Heats adsorption pre-exponential factors deduced indicate that localized (immobile) suggest sputter-cleaned may be approximately clean. model relating shape detector signal time its validity assessed. Measured speed distributions desorbing molecules exhibit an excess slow compared expected simple effusion. At lower surface where longer observed, a peculiar dip observed which appears adsorbing pulses temporarily reduce steady state desorption rate background atoms.