ABSOLUTE MEASUREMENTS OF ELECTRON-LOSS CROSS-SECTIONS OF HE-HYDROGEN AT INTERMEDIATE VELOCITIES( AND C3+ WITH ATOMIC)

Cross sections for electron loss of He<SUP>+</SUP> and C<SUP>3+</SUP> projectile ions on atomic and molecular hydrogen were measured in the 0.5-MeV less than or equal to E less than or equal to 3.5-MeV energy r ange. The measurements of the sigma<INF>H2</INF> / sigma<INF>H</INF> c ross section ratios were made by using an absolutely calibrated hydrog en furnace. The influence of different models describing the form fact or of molecular hydrogen is examined by means of the ratio sigma<INF>H 2</INF> / sigma<INF>H</INF>, which is sensitive to the model adopted, particularly in the case of He<SUP>+</SUP><INF></INF> projectiles. The general behavior of the measured data is analyzed within the independ ent electron approximation including the electron loss (screening and antiscreening contributions), electron capture, and target ionization channels. The connection between the antiscreening mode and the electr on impact ionization of multicharged ions is explored. [S1050-2947(98) 04008-6]