Crossed-molecular-beams investigation of the excitation of ground-state neon atoms by 4.6-eV helium metastables

A molecular beam source has been developed which produces fast metastable helium atoms and was used in a crossed-molecular-beams experiment to measure the absolute differential elastic-collision cross section of these atoms with a velocity-selected beam of ground-state neon atoms. The results at 4.6 eV c.m. show strong evidence of excitations around 5degree and 8degree c.m. The total excitation cross section was estimated at 1.45 A2 and probably originates from potential-energy curve crossings at 0.15 and 0.3 eV