Electron-impact excitation of holmium atoms

The electron-impact excitation of holmium atoms was studied by the method o f extended crossing beams. The cross sections and the optical excitation fu nctions were obtained for odd levels of Ho I, including the 22014 cm(-1) la ser level. Over 99% of the atoms were shown to reside in the ground level p rior to collisions with electrons. Also measured were the excitation cross sections for six even levels, which presumably participate in the formation of inversion population in a gas-discharge holmium vapour laser.