Sticking probabilities of simultaneously adsorbed deuterium and nitrogen on thin iron film at 78 K

A flow technique has been applied to measure the partial sticking probabili ties of deuterium and nitrogen, simultaneously interacting with thin iron f ilms at 78 K. The features of sticking probability dependence on the quanti ty of nitrogen and deuterium consumed have been analysed for both simultane ous and post-dosing D-2 and N-2 adsorption and then have been compared with the corresponding dependencies measured for D-2 and N-2 separately adsorbe d on clean iron film. It was found that simultaneously dosed N-2 and D-2 ad sorb on Fe film with high sticking probabilities (less than or equal to 1) at low coverage. A part of co-adsorbed nitrogen admolecules is removed from the Fe surface due to competitive adsorption of deuterium at higher covera ge. The population of nitrogen simultaneously adsorbed with deuterium on th e Fe film surface is similar to that found for the D-2 adsorption on Fe fil m pre-covered with strongly adsorbed nitrogen admolecules and much higher t han the population obtained after the post-dosing N-2 adsorption on Fe film pre-covered with deuterium adspecies. (C) 1999 Elsevier Science B.V. All r ights reserved.