Electron Scattering by Laser-Excited Barium Atoms

Inelastic and superelastic scattering of 30- and 100-eV electrons by laser-excited $6s6p{}_{}{}^1{}_{}{}^{}P$ and subsequent cascade-populated $6s6p{}_{}{}^3{}_{}{}^{}P$, $6s5d{}_{}{}^1{}_{}{}^{}D$, and $6s5d{}_{}{}^3{}_{}{}^{}D$ Ba atoms have been observed for the first time. Absolute differential cross sections for the singlet and relative scattering intensities for the triplet species have been determined in the 5°-20° angular region. Under the present conditions excitations dominate over de-excitations.