State selective electron capture in slow ¹⁵N⁷⁺+ He, Ne collisions studied using cold-target recoil-ion-momentum spectroscopy

Synopsis Electron capture from He and Ne targets by ¹⁵N⁷⁺ has been studied at projectile velocities of 0.27 and 0.5 a.u. Cold-target recoil-ion momentum spectroscopy was used to simultaneously measure the Q-value and scattering angle. Projectile velocity and target dependence comparisons of single and double electron capture by the projectile were carried out. Single capture from both targets populates the same excited states with nearly similar angular distributions and relative populations. The populated channels in double capture from He and Ne, however, are quite different. One-step and two-step capture mechanisms are proposed for most of the populated channels in double capture.