Excitation cross sections of YII singlet levels during e-Y collisions

One studied experimentally excitation of singlet levels of yttrium single-charged ion in collisions of slow electrons with yttrium atoms. At 50 eV electron energy one measured excitation cross sections of YII 32 spectral lines; for 30 of them one recorded dependence of cross sections on electron energy within 0-200 eV energy range. On the basis of the acquired data one calculated total cross sections of excitation of 11 energy levels, as well as, contribution of cascade excitation for seven levels. The absolute values of excitation cross sections of even and odd levels differ by less than one order of magnitude