Excitation of even levels of Tm II from ground state of thulium atom

The electron-impact excitation of even levels of Tm II from the ground level of the thulium atom is studied by the method of extended crossing beams with recording the optical emission of excited ions. At the exciting electron energy of 50 eV, 54 excitation cross sections are measured. In the electron energy range of 0–200 eV, 12 excitation optical functions are recorded. The most probable channels of the excitation process are discussed.