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 excitati on cross sections of spectral lines of YI are used for the calculation of t he excitation cross sections of energy levels. The levels pertaining to the terms x(2)P degrees, y(2)D degrees,and y(2)F degrees have the largest, tot al excitation cross sections. The contribution by cascade population is abo ut 20% for the levels z(2)D(degrees) and about 3.5% for the levels z(2)F de grees.