Charge-state-dependent collisional energy-loss straggling of swift ions in a degenerate electron gas

Abstract

In order to characterize the statistical aspect of the energy loss in particle penetration, Bohr developed a kinetic theory and applied it to a beam of fast ␣ particles interacting with free electrons. The present study rests on this classical theory of collisional straggling, and it is implemented by using a partially screened Coulomb potential to model the electron-projectile interaction. The deflection angle of electron scattering in this longranged field is calculated analytically within the framework of classical mechanics. The transport fluctuation cross section, which is the basic quantity to the collisional straggling in Bohr's modeling, is determined numerically. By varying the number of bound electrons around the swift He ions, the effect of prefixed charge states in the collisional energy-loss straggling is quantified. An incoherent weighted summation of different fixed charge-state channels is discussed as well, by using normalized probabilities.

Core Electrons in the Electronic Stopping of Heavy Ions

“…hereafter)] has been relatively well understood within linear response [5][6][7] and non-linear response formalisms [8][9][10][11]. The linear and non-linear response approaches have been refined [12][13][14][15][16][17][18][19] but essentially remained limited in their practical applicability to simple metals and simple ions [20,21].…”

Time-dependent screening of a point charge at a metal surface

“…A pioneering work of Manson and co-workers on dynamic screening and interaction of projectiles with many body systems was based, out of necessity, on a simplified codified Hamiltonian to describe this interaction. Stimulated by their work, a great deal of other work incorporating a more detailed description of this interaction was published, including higherorder corrections to the interaction of charged particles with matter [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. With the advent of modern computing facilities, the change in the screening properties of surfaces and in particular the strong non-locality at the surface in general and specifically the ones [29][30][31][32] caused by the presence of the surface states in the dynamics of excited states or the energy loss of charged particles at surfaces became feasible for theoretical investigation.…”