Direct-excitation cross sections for Cd II low-lying excited states by single-electron impact on Cd atoms

Emission cross sections for ten spectral lines transiting from Cd II low-lying excited states formed by single-electron impact on Cd atoms have been measured with a photon-counting technique. Polarizations of these lines have also been examined. By the use of these results and removing the influence of cascade transitions, direct-excitation cross sections for seven low-lying states (5p P12,322, 5s2D32,522, 6s S122, 5d D32,522) have been determined as a function of electron energy. They are found to be of the order of 10-17 cm2 for the 5p and 5s2 states and of 10-18 cm2 for the 6s and 5d states at their maxima.