Electron-capture-to-continuum cusp in U88+ + N2 collisions

P.-M.HILLEBRAND; S.HAGMANN; D.H.JAKUBASSA-AMUNDSEN; J.M.MONTI; P.D.FAINSTEIN; P.D.FAINSTEIN; R.D.RIVAROLA; P.D.FAINSTEIN; R.D.RIVAROLA

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

AMER PHYSICAL SOC

Lugar: New York; Año: 2015 vol. 91 p. 227051 - 2270510

1050-2947

For the collision system U88+ + N2 at a collision energy of 90 MeV/u, the energy distribution of electrons being nonradiatively captured from the target into the projectile continuum has been measured under an angle of 0◦ with respect to the projectile beam axis. This measurement of the electron-capture-to-continuum cusp with the highest effective projectile charge Zeff p= 88 at a near-relativistic collision velocity of β ≈ 0.41 is shown to be characterized by a strong asymmetry in the cusp shape. By comparing the data to measurements of the radiative-electron-capture-to-continuum cusp for the same collision system, the opposite asymmetry of the cusp is traced back to the varying underlying mechanisms. The experimental results are compared with the twotheoretical calculations available for this process, one of them in the semirelativistic impulse approximation and the other in the nonrelativistic continuum-distorted-wave approach. A corresponding fully relativistic treatment may be motivated by the presented experimental data.