Stimulation of argon desorption by an oxygen impurity

The influence of an oxygen impurity on the efficiency of desorption of exci ted atoms and molecules from the surface of crystalline argon is investigat ed. A significant increase in the yield of desorbed particles is observed a t an O-2 concentration of 1 at. % in the argon host matrix. It is shown tha t a xenon impurity does not have a similar effect. Possible mechanisms are proposed for the stimulation of argon desorption by impurity oxygen. One of them may involve the formation of argon microclusters around O- ions near the surface of the crystal. Another mechanism may be due to an increase in the probability of recombination of Ar-2(+) with an electron on account of the hopping of the negative charge between the O-2(-) and Ar-2(+) ions. (C) 2000 American Institute of Physics. [S1063-777X(00)01202-0].