Optical Emissions from Bombarding Atmospheric Gases with Heavy Ions.

摘要

The optical emissions were studied from both nitrogen and oxygen targets contained in a differentially pumped cell and bombarded by particles of H3(+) with an energy of 1 MeV. The radiation was analyzed with a 1-meter air Czerny-Turner spectrometer capable of providing an instrumental line width of 0.01 nm. We covered the range from 320 to 850 nm. Most of the work was done with a line width of 0.1 nm, and some with a smaller value. Numerous lines from excited states in monatomic emitters and bands from states in molecular systems were observed. Relative intensities of the lines were measured and compared with values in the experimental literature and also with calculated transition probabilities. There was poor agreement with the experimental data provided by others, but excellent agreement with the theory. This light source is clearly superior to most others for the measurement of relative line intensities. The nitrogen data failed to show any lines from neutral atoms, although such lines are seen when electrons are the initiating particles. On the other hand, oxygen shows very strong lines from the neutral atom; both nitrogen and oxygen show lines from the singly ionized atom. While the nitrogen data reveal contributions from both the neutral and singly ionized molecules, the oxygen shows bands only from the molecular ion. The absence of bands from neutral oxygen molecules is easily understood in terms of the potential curves for that structure, but the absence of lines from the neutral nitrogen atom remains obscure. (jhd)