Excitation of doublet states of yttrium atom by electron impact

The excitation of odd doublet states of yttrium atom by slow monoenergetic electrons is investigated. The obtained experimental values of the excitation cross sections of spectral lines of YI are used for the calculation of the excitation cross sections of energy levels. The levels pertaining to the termsx $x^2P^\circ$, $y^2D^\circ$, and $y^2F^\circ$ have the largest total excitation cross sections. The contribution by cascade population is about $20\%$ for the levelsz $z^2D^\circ$ and about $3.5\%$ for the levelsz $z^2F^\circ$.