Excitation of autoionization states (1s2s2p) 4Pj lithium atom by electron impact

For the first time the electron excitation function of autoionization states (1s2s2p) 4P1/2,3/2 of lithium atom is measured in the energy collision range from the level excitation threshold up to 90 eV. Measurements are performed by the electron spectroscopy with using the technique of crossing electron and atomic beams at the magic observation angle Θ 54.7 deg. The experimental installation provides the energy resolution not worse 0.4 eV. The analysis of the observed intensive subthreshold structure permits to define the existence of autobreaking states of the negative ion Li with excitation thresholds 58.2 ± 0.1 and 59.5 ± 0.1 eV in the autoionization energy range