Sticking probabilities, redistribution phenomena and desorption spectra for nitrogen on molybdenum and titanium films

Abstract

The kinetics of the interaction of nitrogen with vacuum-deposited films of molybdenum and titanium have been investigated, utilizing ultra-high vacuum techniques, in the range 78–300°K. The sticking probabilities for clean films are : molybdenum, 300°K, 0.75; 78°K, 0.9; titanium, 300°K, 0.50; 78°K, 0.75. A physical model of the film surface is described which takes into account multiple collisions and allows and estimate to be made of the sticking probability for a perfectly smooth surface. A heavily populated adsorption state with adsorption heats ranging from 6 to 20 kcal/mole has been characterized for both molybdenum and titanium films by the observation of redistribution phenomena, isotherms, isosteric heats and desorption spectra.