Atoms in high-lying Rydberg states with large values of the principal quantum number n, n ⩾ 300, form a valuable laboratory in which to explore the control and manipulation of quantum states of mesoscopic size using carefully tailored sequences of short electric field pulses whose characteristic times (duration and/or rise/fall times) are less than the classical electron orbital period. Atoms react to such pulse sequences very differently than to short laser or microwave pulses providing the foundation for a number of new approaches to engineering atomic wavefunctions. The remarkable level of control that can be achieved is illustrated with reference to the generation of localized wavepackets in Bohr-like near-circular orbits, and the production of non-dispersive wavepackets under periodic driving and their transport to targeted regions of phase space. The testing of these control schemes, together with their reversibility, through the creation of electric dipole echoes in Stark wavepackets, is also described. New protocols continue to be developed that will allow even tighter control with the promise of new insights into quantum-classical correspondence, information storage in mesoscopic systems, physics in the ultra-fast ultra-intense regime and nonlinear dynamics in driven systems.

For the first time, charge-changing reactions in collisions of two negative ions were investigated. Absolute cross sections for mutual ionization were determined for H− colliding with H−, using crossed beams and coincident detection of the reaction products. The centre-of-mass energy range covered in the experiment extended from 1.5 keV to 90 keV for the reaction channel H− + H− to H0 + H0 + 2e− and from 4 keV to 40 keV for the channel H− + H− to H0 + H+ + 3e−. The measured cross sections are compared with results of CTMC calculations obtained with different model potentials for the interaction between the outer electron and the H0 core

The three-body system is analyzed in relation to the calculation of atomic scattering cross sections. A method is presented to generate the initial electronic conditions for the classical-trajectory Monte Carlo method in the case where the active electron is subject to non-Coulomb interactions.The method is then applied to study the collisions of H+ with He and Li+ targets in the intermediate-to high-energy range. Single-electron capture and single-ionization total cross sections are presented for both collision systems. In the case of He targets, total cross sections for double ionization and singly differential cross sections for free-electron production are also calculated. Cross sections and initial electronic distributions are obtained with both Coulomb and model interactions and compared. Good agreement is found between theoretical and experimental results, except for the double ionization of He.

Presented here is a description of the ionization of hydrogen and hydrogenic

Owing to the use of beryllium in fusion reactors and the consequent need to model and diagnose plasmas containing this species of impurity, cross sections are presented here for inelastic collisions of 1-1000 keV/u Be q+ (q=2-4) with H and H 2. In particular, the classical trajectory Monte Carlo technique is used to compute total cross sections for (i) ionization, (ii) state-selective excitation, and (iii) state-selective charge transfer.

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The authors study the classical-quantum correspondence for ionization in three-body fast ion-atom collisions. The existence of a classical limit of the quantum mechanical transition probabilities as a function of the momentum transferred to the electron during the collision, the impact parameter, the energy and angle of the emitted electron, and the initial quantum level of the target is investigated. A well behaved classical limit is shown to exist for large momentum transfers whereas ionization by small momentum transfers or at large impact parameters is shown to be classically suppressed. It is found that ionization at small impact parameters does not possess a well-defined classical limit. Modifications of classical trajectory Monte Carlo (CTMC) methods to account for non-classical ionization are suggested. Applications related to recent data for electron ejection into large angles are presented.