The three-body system is analyzed in relation to the calculation of atomic scattering cross sections. A method presented generate initial electronic conditions for classical-trajectory Monte Carlo case where active electron subject non-Coulomb interactions. then applied study collisions ${\mathrm{H}}^{+}$ with He and ${\mathrm{Li}}^{+}$ targets intermediate- high-energy range. Single-electron capture single-ionization total sections are both collision systems. In targets, double ionization...

Doubly and singly differential cross sections for electron emission have been calculated by means of the classical trajectory Monte Carlo method ${p}^{+}$, ${p}^{\mathrm{\ensuremath{-}}}$, ${\mathrm{He}}^{2+}$+He systems at impact energies 50 100 keV/amu. The calculations ${p}^{+}$ exhibit capture to continuum peak agree in both shape magnitude with experimental data. Analysis trajectories has helped understand dynamical formation this peak. dependence on projectile charge (-1, +1, +2) is...

Atoms in high-lying Rydberg states with large values of the principal quantum number n, n {ge} 300, form a valuable laboratory which to explore control and manipulation mesoscopic size using carefully tailored sequences short electric field pulses whose characteristic times (duration and/or rise/fall times) are less than classical electron orbital period. react such pulse very differently laser or microwave providing foundation for new approaches engineering atomic wavefunctions. The...

The authors study the classical-quantum correspondence for ionization in three-body fast ion-atom collisions. existence of a classical limit quantum mechanical transition probabilities as function momentum transferred to electron during collision, impact parameter, energy and angle emitted electron, initial level target is investigated. A well behaved shown exist large transfers whereas by small or at parameters be classically suppressed. It found that does not possess well-defined limit....

We study the ionization of Rydberg atoms by half-cycle electromagnetic pulses as a function duration covering broad range time intervals connecting adiabatic and sudden regimes. The threshold fields for lie on universal classical scaling invariant curve. present quantum mechanical results which agree well with n-2 field found experimentally is linear approximation to curve tangent in region where pulse order orbital period atom. predict existence an ultrashort limit scales n-1. Effects due...

Total cross sections for state-selective electron capture in collisions between ions and alkali-metal atoms have been calculated by means of a three-body classical-trajectory Monte Carlo (CTMC) method using model potentials to describe the electron--ionic-core interactions. Calculations performed ${\mathrm{Na}}^{+}$-Na(28d) ${\mathrm{N}}^{5+}$ ${\mathrm{Ar}}^{8+}$-Cs(6s) collisions. The collision velocity range corresponds...

Presented here is a description of the ionization hydrogen and hydrogenic ions by antiproton impact, based on very large scale numerical solutions time-dependent Schr\"odinger equation in three spatial dimensions analysis topology electronic eigenenergy surfaces plane complex internuclear distance. Comparison made with other theories recent measurements.

We present a theoretical analysis of the above-surface neutralization highly charged ions in front LiF. The study is based on assumption that dominant electron transfer occurs classically allowed region. Estimates critical distances and corresponding quantum numbers for capture from an ionic crystal within classical-overbarrier (COB) model are presented, which differ considerably results metals. role dielectric response LiF investigated. In addition, classical-trajectory simulations...

A classical phase-space model of the hydrogen molecule is presented and applied to study electron-capture -ionization processes in collisions fully stripped ions with ${\mathrm{H}}_{2}$ at intermediate impact energies charge states from 1 10. The based on independent-electron impact-parameter approximations. electron--impinging-ion electron--target-nuclei interactions are exactly taken into account. interaction between electrons approximated by potentials. calculated total cross sections for...

An impulse approximation for ionizing collisions of clothed ions with atoms is used to explain the origin an anomalous oscillation in ejected electron spectrum region binary peak. In addition, measurements which evidence this feature 1-MeV/u ${\mathrm{U}}^{21+}$ colliding helium are presented. It shown that behavior arises from interference structures elastic differential cross section scattering target electrons impinging ion and it associated well-known phenomenon rainbow scattering.

The relatively recent advent of low energy antimatter projectiles has spurred a rapid advance in the comparison matter- and antimatter-atom collisions. These experimental studies have turn stimulated great deal theoretical effort to explain their results, together both theory experiment shed new light on dynamics ion-atom authors review these developments with particular emphasis processes ionization charge transfer.

The kicked atom is realized experimentally by exposing potassium $\mathrm{np}$ Rydberg atoms with $n\ensuremath{\sim}388$ to a sequence of up 50 half-cycle pulses whose duration much shorter than the classical electron orbital period. survival probability observed have broad maximum for pulse repetition frequencies near frequency. Comparisons detailed trajectory Monte Carlo simulations show that this behavior provides an unambiguous signature dynamical stabilization. further hydrogen is,...

Results of crossed-beam measurements cross sections differential in ejected electron energy and angle for ionization atomic hydrogen by 20--114-keV protons are reported. Secondary electrons were measured over an range 1.5--300 eV angular 15\ifmmode^\circ\else\textdegree\fi{}--165\ifmmode^\circ\else\textdegree\fi{}. Atomic-hydrogen targets produced a radio-frequency discharge source with dissociation fraction about 74%. Ratios H to those ${\mathrm{H}}_{2}$ obtained from on the mixed target....

We demonstrate that strong transient phase-space localization can be achieved by the application of a single impulsive ``kick'' in form short (600 ps) unidirectional electric-field pulse to strongly polarized, quasi-one-dimensional Rydberg atom. The underlying classical dynamics is analyzed and it shown results from focusing effect analogous rainbow scattering. Moreover, essential features analysis remain valid quantum-mechanical treatment system terms its Husimi distribution. degree...

Wave packets comprising a superposition of very-high-lying Rydberg states have been created using half-cycle pulse (HCP). The properties the wave packet are probed second HCP that is applied following variable time delay. ionizes fraction atoms and survival probability exhibits pronounced oscillations associated with quasiperiodic evolution packet. Good agreement found between experimental data results classical trajectory Monte Carlo simulation demonstrating that, for times investigated,...

Classical phase-space models of the hydrogen molecule and helium are utilized to study shell subshell electron-capture processes in collisions fully stripped ions on charge states from 1 15 with ${\mathrm{H}}_{2}$ He at intermediate impact energies (20--200 keV/amu). Autoionization after double electron capture is approximated found be an important channel for high projectile charges. The resulting (n,l) distributions proton as well total cross sections very good agreement experimental data....

We perform classical molecular dynamics simulations of the chemical sputtering deuterated amorphous carbon surfaces by D and D2, at energies 7.5–30 eV D−1. Particular attention is paid to preparation target for varying impact projectile fluence, energy species, vibrational state D2 projectiles, as well variation in yields with surface projectile. The methane acetylene per deuteron, obtained atomic agree quantitatively recent experimental values. study distribution sputtered their kinetic...

We demonstrate that strongly polarized quasi-one-dimensional very-high-n (potassium) Rydberg atoms can be produced by photoexcitation of selected Stark states in the presence a weak dc field. Calculations show that, for $m=0$ states, significant occurs only vicinity Stark-shifted s, p, and d levels, those located near level have sizable polarizations. These predictions are confirmed experiment. The degree polarization product is analyzed studying differences their ionization characteristics...

The impulse or binary encounter approximation for ion-atom collisions is extended to treat the non-Coulomb interaction between a clothed projectile ion and target electrons. This model shown reproduce unexplained enhancement of zero-degree peak partially stripped ions over that equivelocity fully has recently been observed experimentally in Fq++H2, He collisions. Very good agreement obtained theory experiment and, furthermore, this used illuminate underlying dynamics which leads enhancement.

The experimentally observed high-l-state population of ions excited in ion-solid interactions differs sharply from l-state populations produced ion-atom collisions. We have studied the dynamics electronic excitation and transport within framework a classical theory for ${\mathrm{O}}^{2+}$ (2-MeV/u) traversing C foils. resulting delayed-photon-emission intensities are found to be very good agreement with experiment. Initial phase-space conditions been obtained both classical-trajectory Monte...

Excitation of atomic hydrogen in initial quantum levels ${\mathit{n}}_{\mathit{i}}$=1,2,3 colliding with multiply charged ions charge states q from 1 to 26 is investigated the impact energy range 10 (keV/u)/${\mathit{n}}_{\mathit{i}}^{2}$--10 MeV/u, by means classical trajectory Monte Carlo, many-state orbital close-coupling, and symmetric eikonal formalisms. This extensive compilation theoretical calculations confirms feasibility an empirical scaling relation (\ensuremath{\sigma}/q vs E/q)...

We demonstrate a protocol to create localized wave packets in very-high-$n$ Rydberg states which travel nearly circular orbits around the nucleus. Although these slowly dephase and eventually lose their localization, motion can be monitored over several orbital periods. These represent closest analog yet achieved original Bohr model of hydrogen atom, i.e., an electron classical orbit The possible extension approach ``planetary atoms'' highly correlated stable multiply excited is discussed.

We have measured total sputtering yields for impact of slow ( $\ensuremath{\le}100\mathrm{eV}$) singly and doubly charged ions on LiF. The minimum potential energy necessary to induce (PS) from LiF was determined be about 10 eV. This threshold coincides with the produce a cold hole in valence band by resonant neutralization. allows first unambiguous identification PS induced holes. Further stepwise increase yield higher projectile energies provides evidence additional defect-mediated...

Measurements in which $K(\mathrm{np})$ Rydberg atoms with $n\ensuremath{\sim}388$ are subject to a train of up 50 half-cycle pulses reported and reveal peak the atomic survival probability for pulse repetition frequencies near classical orbital frequency. Classical calculations show that this behavior is associated dynamical stabilization periodic orbits phase space around stable islands form identified. This work provides first direct evidence periodically kicked atom.