Asymptotic energy dependence of projectile excitation in relativistic ion-atom collisions

The Coulomb excitation of inner-shell electrons around heavy and highly-charged projectile ions impinging on light targets is investigated in the highly relativistic energy regime for projectiles as heavy as gold (Z = 79). First-order time dependent perturbation theory is employed for treating the interaction of the active electron with the light target, and exact relativistic Coulomb-Dirac wave functions are used for the description of electronic states in the strong field of the projectile nucleus. The energy dependence of transition probabilities and partial cross sections is studied up to extreme relativistic energies of hundreds of GeV/u and beyond. An analytic representation of the asymptotic energy dependence of the projectile excitation cross section complements the numerically calculated impact parameter dependent probabilities and cross sections providing additional insights. (orig.)Available from TIB Hannover: RO 801(2002-14) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Electron loss from 1.4 MEV/u U"4","6","1"0"+ ions colliding with Ne, N_2 and Ar targets

Absolute, total, single, and multiple electron loss cross sections are measured for 1.4 MeV/u U"4","6","1"0"+ ions colliding with neon and argon atoms and nitrogen molecules. It is found that the cross sections all have the same dependence on the number of electrons lost and that multiplying the cross sections by the initial number of electrons in the 6s, 6p, and 5f shells yields good agreement between the different projectiles. By combining the present data with previous measurements made at the same velocity, it is shown that the scaled cross sections slowly decrease in magnitude for incoming charge states between 1 and 10 whereas the cross sections for higher charge state ions fall off much more rapidly. (orig.)Available from TIB Hannover: RA 3692(04-18) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Electron stripping cross sections for fast, low charge state uranium ions

Cross sections for projectile electron loss for U"1"0"+ and U"2"8"+ colliding with H_2, N_2 and Ar were calculated using the n-body classical trajectory Monte Carlo method. The calculations include electrons on both nuclear centers and all electron-electron and electron-nuclear interactions between centers. Multiple ionization is inherently included in these many electron calculations. Overall, except for the H_2 target where the projectile stripping is overestimated by a factor of two, the calculated cross sections are in reasonable accord with available data and the recent beam lifetime measurements from GSI-Darmstadt. For energies less than 100 MeV/u, the N_2 and Ar cross sections do not scale as E"-"1"."0 as predicted by one-electron theories. (orig.)Available from TIB Hannover: RO 801(04-17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman