The question of how to develop methods and devices for the detection of low concentrations of various organic compounds—in particular, explosive substances—is currently attracting much attention. In this connection, there is great interest in laser ionization methods, especially the method of surface laser desorption/ionization from nanostructured surfaces, including porous silicon. In this case, a separate problem is to establish a mechanism for forming ions of the molecules of interest. This paper uses the example of trinitrotoluene to investigate the process of desorption and formation of negative ions of nitroaromatic compounds when a laser acts on porous silicon at atmospheric pressure. The dependence of the ion yield on the intensity of the exciting radiation has been measured. It is established that negative ions of trinitrotoluene form directly on the surface of nanoporous silicon.
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