Resonant Transfer and Excitation in Li-Like F Colliding with H₂

We have measured coincidences between x rays and projectiles that have captured one electron in F6+ + H2 collisions at projectile energies between 15 and 33 MeV. The cross sections for capture and simultaneous x-ray emission as a function of projectile energy show clear structures. Indications of an unexpectedly high population of high-n states predominantly formed by resonant transfer and excitation (RTE) were found. Above the Kln (n\u3e1) RTE resonance energies another maximum was observed

Collective multipole expansions and the perturbation theory in the quantum three-body problem

The perturbation theory with respect to the potential energy of three particles is considered. The first-order correction to the continuum wave function of three free particles is derived. It is shown that the use of the collective multipole expansion of the free three-body Green function over the set of Wigner $D$-functions can reduce the dimensionality of perturbative matrix elements from twelve to six. The explicit expressions for the coefficients of the collective multipole expansion of the free Green function are derived. It is found that the $S$-wave multipole coefficient depends only upon three variables instead of six as higher multipoles do. The possible applications of the developed theory to the three-body molecular break-up processes are discussed.Comment: 20 pages, 2 figure

Charge- And Angle-correlated Inelasticities In Collisions Of Bare Fast Carbon Ions With Neon

We have studied the detailed energy balance in collisions of 10-MeV C6+ ions with Ne. In these collisions, the Ne is multiply ionized and the C ion may emerge as either C6+ or C5+. Projectile energy loss and scattering angle for a given carbon-ion charge state were determined in a high-resolution magnetic spectrograph and were measured in coincidence with the formation of a given Ne recoil-ion charge state. The amount of energy transferred to the continuum electrons exceeds, by far, the sum of the values of the ionization potentials. © 1988 The American Physical Society

Ionization in fast atom-atom collisions: The influence and scaling behavior of electron-electron and electron-nucleus interactions

We report cross sections for ionization of He coincident with electron loss from He, Li, C, O, and Ne projectiles. For He, Li, C, and O projectiles, the cross sections were measured directly, while the Ne cross sections were obtained by transforming results for He projectiles colliding with Ne. We find that, at energies of about 100–500 keV/u, neutral projectiles can ionize a He target almost as effectively as a charged projectile. The contribution to ionization due to electron-electron interactions is found to scale with the number of available projectile electrons. Comparing ionization by the bound electrons on projectiles to ionization by free electrons, we find that the cross sections for ionization by bound electrons are systematically smaller than those for free electrons

Comparison of quantum mechanical and classical trajectory calculations of cross sections for ion-atom impact ionization of negative - and positive -ions for heavy ion fusion applications

Stripping cross sections in nitrogen have been calculated using the classical trajectory approximation and the Born approximation of quantum mechanics for the outer shell electrons of 3.2GeV I$^{-}$ and Cs$^{+}$ ions. A large difference in cross section, up to a factor of six, calculated in quantum mechanics and classical mechanics, has been obtained. Because at such high velocities the Born approximation is well validated, the classical trajectory approach fails to correctly predict the stripping cross sections at high energies for electron orbitals with low ionization potential.Comment: submitted to Phys. Rev.