Influence of the radiationless transitions on an intensity of the optical radiation emitted by excited atoms ejected from solids by an ion beam

Abstract

The excited atoms of the target material are ejected during an ion bombardment of solids. These atoms belong to one of two velocity groups — fast or slow. The fast atoms arise in binary collisions of bombarding ions with target atoms and the slow ones are knocked out as a result of a sputtering process. Excited atoms flying off the surface intersect the solid-vacuum boundary and can transfer their excitation energy in the radiationless transitions mainly of the resonance ionization type. The probability of this process depends strongly on the electronic energy level structure of solids and a velocity of ejected atoms. On this statement our method of the electronic energy level structure of solids study is based by means of investigation of excited atoms velocity spectrum.

On the results of paper [4] we remark that in their experimental conditions the surface of the lithium target was apparently strongly oxidized. Using our method and results of paper [4] we can estimate the energy width of the conduction band of Li₂O to 0.4 eV.

In general the cascade corrections to the mean life times of excited atoms may be important and one can take them into account. The detailed analysis of the influence of the cascade corrections to the mean life times of upper excited states of some TiI lines (λλ 5210 Å, 5064 Å, 4682 Å, 3981 Å, 4533 Å, 4856 Å) was carried out. It was found that in the case when our method was applied to determination of the work function of metallic titanium the cascade corrections either are negligible or not necessary.