We have measured the relative optical-excitation functions and polarizations of the K, Rb, and Cs resonance lines, using crossed electron and atom beams, for electron energies from threshold to 1500 eV. The electron energy resolution was ∼0.25 eV for energies below 13 eV, and the atom beam was optically thin. The atomic resonance-level ($n^{2}P$) excitation functions have been normalized to the Born theory in the high-energy limit. Comparisons are made with other measurements and calculations. The polarizations and total cross sections for H, Li, Na, K, Rb, and Cs are also compared with each other in reduced units to investigate systematic behavior.

• Received 30 September 1977

DOI:https://doi.org/10.1103/PhysRevA.17.551