Orientation dependence for multiple electron transfer from homonuclear diatomic molecules in collisions with slow highly charged ions

Orientation dependence is investigated for multiple electron transfer from homonuclear diatomic molecules in slow collisions with highly charged ions. Angular distributions of the molecular axis with respect to the incident beam are calculated for r-electron transfer (1 less than or equal to r less than or equal to 10) from nitrogen molecules with the three-center Coulombic over-barrier model developed by the present authors. The quadrupole anisotropy parameter beta (2) obtained indicates universal variation with the incident charge q; beta (2) similar or equal to -1 at the threshold (i.e. q = r), taking the minimum of beta (2) similar or equal to -0.1 at q similar or equal to r, and converging to beta (2) similar or equal to -0.06 for q much greater than r. The present model generally derives oblate distributions (beta (2) < 0), in striking contrast to the statistical energy-deposition model, which gives prolate distributions (beta (2) > 0) for multiple ionization by fast-ion impact.