SUPERELASTIC ELECTRON-SCATTERING FROM POTASSIUM

Measurements of the orientation and alignment parameters have been per formed on potassium atoms using a superelastic scattering technique. I n these experiments a laser beam is tuned to the 4(2)S(1/2)-4(2)P(3/2) transition in potassium. Electrons are scattered from these excited a toms and those electrons that gain energy in the collision are detecte d. These superelastic electrons carry information about the orientatio n and alignment parameters which describe the scattering process. Orie ntation and alignment parameters have been measured at an electron ene rgy of 10 eV referred to the ground state and over an angular range fr om 0 degrees to 150 degrees. These parameters are in excellent agreeme nt with those predicted using the convergent close-coupling theory.