ORIENTATION EFFECTS IN MULTIPLE IONIZATION OF MOLECULES BY FAST IONS

The multiple ionization and dissociation of N-2 molecules by fast Heions was studied by the coincident measurement of correlated fragment- ion momenta using a position-and time-sensitive multiparticle detector . The dependence of the cross section on the alignment of the molecula r axis with respect to the beam axis was determined. The results show that for higher degrees of ionization the cross section has a pronounc ed minimum for molecules oriented perpendicular to the beam. The quant itative interpretation of the observed results is based on an extended version of the statistical energy deposition model.