On the applicability of the impulse approximation for radiative electron capture into bound and continuum states

Elastic resonant and nonresonant differential scattering of quasifree electrons fromB4+(1s)andBenis1, Zouros2, Gorczyca3 et al. 2004Phys. Rev. A3432011View full textAdd to dashboardCite

“…The collisional energy dependence of the measured projectile excitation cross sections exhibited characteristics usually associated with electron impact phenomena [18][19][20][21]. Thus, strong resonance phenomena observed in resonance transfer excitation (RTE) measurements [22,23] could be associated with RE, radiative electron capture (REC) corresponded to radiative recombination (RR) [24][25][26][27] and electron impact threshold, target recoil and electron exchange effects, usual signatures of electron impact excitation and ionization, were clearly identified in the excitation [28][29][30] and ionization [31][32][33][34][35][36][37] of projectile ions in ion-atom collisions, respectively.…”

Bremsstrahlung during electron capture to continuum

“…Using the nonrelativistic semiclassical scattering theory (where the electron is treated quantum mechanically), accounting for the coupling to the radiation field in first order and neglecting the electron-target interaction in the propagator as well as in the final electronic state, one obtains the following transition amplitude (Jakubassa-Amundsen, 1987):…”

“…The strong potential Born approximation is obtained from (3.7) by a renormalization of the off-shell function (Jakubassa-Amundsen, 1987) such that it agrees with the projectile continuum eigenstate c P q in the free electron limit Z T ¼ 0.…”

“…For Z T ¼ 0, one has E T i ¼ 0 and q ¼ Àv (as required by j T i ðq þ vÞ), and it follows from (3.9) that this on-shell approximation becomes exact. Indeed, for light targets, the impulse approximation is excellent down to collision velocities v % Z P for electron momenta k 0 f tv (Jakubassa-Amundsen, 1987).…”

Theoretical Models for Atomic Charge Transfer in Ion-Atom Collisions

“…In the Coulomb case, such a comparison is often falsified because in most cases additional approximations have to be made. As an example, a comparison between the impulse approximation arad the strong potential Born theory for REC and RI reveals 213 that for frequencies close to the K-REC peak, SPB and IA give nearly equal results for both bound-state capture and capture to the continuum up to an electron momentum around v (in the projectile frame).…”