Markush P. Excitation and ionization by interaction of electrons with gas-phase sulfur and selenium

Elementary processes occuring during interaction of electrons with gas-phase sulfur and selenium have been studied for the first time using methods of mass spectrometry, photon spectroscopy and electron spectroscopy. It has been found that atoms and molecules are equally formed in the process of sulfur and selenium evaporation. The energy dependences of ion formation effective cross section of sulfur and selenium atoms and molecules were measured as well as the energy appearances of the ions were determined. It has been shown that the excitation of electron-vibrating levels of the triplet state of S2 and Se2 molecules occur in the energy region below 20 eV, while at 50 eV the S and S+ as well as Se and Se+ become excited. It has been found for the first time that the atoms of substances under investigation are formed in the excited state through dissociation of the S2 and Se2 molecules. The total effective cross sections of positive ion formation in sulfur and selenium vapors were measured for the first time by electron impact in the energy region from the threshold to 16 eV. The ionization threshold for the sulfur (9.5 еV) and selenium (8.2 еV) were determined. It has been found that the resonance electron capture by the components of sulfur and selenium vapor takes place in the energy region of 0-10 eV.