Examination of a molecular Se beam by mass spectrometry with electron ionization

The methodology and results of mass-spectrometric studies of producing positive ions as a result of the dissociative ionization of a molecular selenium beam by electron impact are discussed. The appearance energies of fragment ions were determined from the ionization efficiency curves. The dynamics of production of molecular selenium ions in the temperature range of 420–500 K was also examined. The energy dependences of efficiency of production of singly charged Se$_n^+$ ions for $n$ = 1–4 and the doubly charged selenium ion in the interval from the threshold to 36 eV were studied for the first time. The observed specific features of effective ionization cross sections were analyzed.