Vertical incidence of slow Ne10+ ions on an LiF surface: Suppression of the trampoline effect

in Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2001), 182

We present a Monte Carlo simulation of the neutralization of a slow Ne10+ ion in vertical incidence on an LiF(100) surface. The rates for resonant electron transfer between surface F- ions and the ... [more ▼]

We present a Monte Carlo simulation of the neutralization of a slow Ne10+ ion in vertical incidence on an LiF(100) surface. The rates for resonant electron transfer between surface F- ions and the projectile are calculated using a classical trajectory Monte Carlo simulation, We investigate the influence of the hole mobility on the neutralization sequence. It is shown that backscattering above the surface due to the local positive charge up of the surface ("trampoline effect") does not take place. (C) 2001 Elsevier Science B.V. All rights reserved. [less ▲]

Modular recursive Green's function method for ballistic quantum transport

in Physical Review. B (2000), 62(3), 1950-1960

A modification of the standard recursive Green's function method for quantum transport through microstructures is presented which is based on the decomposition into separable substructures. The Green's ... [more ▼]

A modification of the standard recursive Green's function method for quantum transport through microstructures is presented which is based on the decomposition into separable substructures. The Green's functions for these modules are joined by discretized Dyson equations. Nonseparable structures can thereby be calculated with the help of a few recursions with high accuracy. We apply this method to the calculation of ballistic quantum transport through a circular and stadium-shaped quantum dot for high mode numbers to test semi-classical predictions in detail. Among other results we find the breakdown of the semiclassical approximation for long path lengths which is due to the spreading of wave packets in the cavity. [less ▲]

Charge-state evolution of highly charged ions transmitted through microcapillaries

in Physical Review. A (2000), 61(2),

The charge-state evolution of highly charged ions transmitted through microcapillaries is studied theoretically by a classical trajectory Monte Carlo simulation.: The interaction of highly charged ions ... [more ▼]

The charge-state evolution of highly charged ions transmitted through microcapillaries is studied theoretically by a classical trajectory Monte Carlo simulation.: The interaction of highly charged ions with the internal surface of the capillary is treated within the framework of dielectric response theory. We analyze the distance of closest approach and the angular distributions of the highly charged ions at the exit of the microcapillary. We find the charge-state fraction of transmitted N6+ projectiles, in: good agreement with first measurements. Moreover, our calculations indicate that grazing collisions with the microcapillary surface hold the promise of direct observation of charge transfer and hollow-atom formation at a large distance from the surface. [less ▲]

Interaction of highly charged ions with microcapillaries

in PHYSICA SCRIPTA (1999), T80B

The transmission of highly charged ions (HCI) through microcapillaries is investigated. The interaction of an HCI with the internal surface of the capillary is described in terms of a classical image ... [more ▼]

The transmission of highly charged ions (HCI) through microcapillaries is investigated. The interaction of an HCI with the internal surface of the capillary is described in terms of a classical image potential. For Neq+ projectiles transmitted through a Ni capillary the impact parameter distribution and angular distribution of ions leaving the microcapillary is determined. We consider both a narrowly focussed and a dispersive incident beam relative to the acceptance angle of the capillary. Our results are compared with recent experiments. [less ▲]

Interaction of highly charged ions with microcapillaries

in Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (1999), 154(1-4), 307-311

We analyze the transmission of highly charged ions (HCI) through microcapillaries. The interaction of an HCI with the interval surface of the capillary is treated within the framework of linear response ... [more ▼]

We analyze the transmission of highly charged ions (HCI) through microcapillaries. The interaction of an HCI with the interval surface of the capillary is treated within the framework of linear response. In the limiting case of an ideal conducting cylindrical surface, the interaction reduces to a classical image potential. For Neq+ projectiles transmitting through a Ni capillary calculations for the impact parameter distribution and angular distribution of hollow atoms are presented. We find the fraction of transmitted projectiles which are partially neutralized in good agreement with recent experiments. (C) 1999 Elsevier Science B.V. All rights reserved. [less ▲]

Geometry-dependent scattering through ballistic microstructures: Semiclassical theory beyond the stationary-phase approximation

in Physical Review. B (1997), 56(12), 7589-7597

The conductance of a ballistic microstructure shows strong fluctuations as a function of the Fermi wave number. We present a semiclassical-theory that describes these fluctuations in terms of bundles of ... [more ▼]

The conductance of a ballistic microstructure shows strong fluctuations as a function of the Fermi wave number. We present a semiclassical-theory that describes these fluctuations in terms of bundles of short trajectories. These trajectories provide the dominant contribution to electron transport through a weakly open microstructure. For the coupling between the quantum wires and the cavity, contributions beyond the stationary phase approximation are taken into account giving rise to diffraction effects. A comparison with full quantum calculations for st rectangular billiard is made. The peak positions of the power spectrum agree very well between the quantum and semiclassical theories. Numerical evidence is found for the breakdown of the semiclassical approximation for long paths. A simple explanation in terms of the dispersion of the semiclassical wave packet in the interior of the cavity is proposed. [less ▲]