PARTIAL AND TOTAL CROSS-SECTIONS FOR SINGLE-ELECTRON CAPTURE BY AR8-2400-EV ENERGY-RANGE( FROM HE IN THE 400)

Charge-exchange processes in 400-2400 eV Ar8+-He collisions are invest igated: high energy resolution ion beam spectroscopy is performed with a recoil ion source (RIS) built in GANIL, total and partial cross sec tions for single-electron capture are measured using retarding field a nd energy gain techniques. Comparison with previous experimental resul ts for total charge-exchange cross sections shows a rather good agreem ent and confirms the independence of these cross sections on the colli sion energy in the studied range. In contrast partial charge-exchange cross sections are shown to depend strongly on the collision energy. T he experimental data are compared with theoretical results in the semi -classical impact parameter frame and with predictions made by other a uthors using the Landau-Zener model.