[en] We present a theoretical framework for studying dynamics of open quantum systems. Our formalism gives a systematic path from Hamiltonians constructed by first principles to a Monte Carlo algorithm. Our Monte Carlo calculation can treat the build-up and time evolution of coherences. We employ a reduced density matrix approach in which the total system is divided into a system of interest and its environment. An equation of motion for the reduced density matrix is written in the Lindblad form using an additional approximation to the Born-Markov approximation. The Lindblad form allows the solution of this multi-state problem in terms of Monte Carlo sampling of quantum trajectories. The Monte Carlo method is advantageous in terms of computer storage compared to direct solutions of the equation of motion. We apply our method to discuss coherence properties of the internal state of a Kr³⁵⁺ ion subject to spontaneous radiative decay. Simulations exhibit clear signatures of coherent transitions

[en] The interaction of highly charged ions (HCIs) with matter at low velocities continues to pose a considerable challenge to theory. After a brief overview over the scenario of neutralization and relaxation, we focus on one particularly difficult problem: reliable estimates for two-electron transition rates for highly charged ions interacting with insulator surfaces. Three different processes are considered: intra-atomic Auger, Auger capture and Auger deexcitation. They represent input for simulations of neutralization of HCIs near surfaces. Simple universal estimates as functions of the distance to the surface, as well as initial and final state populations are presented which are believed to provide reasonable order of magnitude estimates

[en] We present a Monte Carlo simulation of the neutralization of a slow Ne¹⁰⁺ ion in vertical incidence on an LiF(1 0 0) 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

[en] We have studied chemical sputtering, hydrogen retention and other products of particle-surface interactions in the least known, intermediate-to-low range of impact energies (1-30 eV/D), with atomic and molecular projectiles of deuterated amorphous carbon surfaces. Results from atomistic, molecular dynamics (MD) modeling using massive computation have been benchmarked against 'in house' particle beam experiments, enhancing its predictive capabilities. We have extended previous MD simulations for well defined ion beam experiments to plasma-bombardment environments using predefined distributions of impact particles in energy, angle, and angular momentum. Initial comparison with available plasma-irradiation experimental data is encouraging. The quality of the existing interatomic potentials and research opportunities in the development of new potentials for mixed fusion materials are discussed.

[en] We study theoretically and experimentally the population dynamics of the internal state of 60 MeV/u Kr³⁵⁺ ions traversing amorphous carbon foils. A quantum transport theory is developed that incorporates the state mixing induced by the wake field of the ion as well as all the coherences generated by the collisional and radiative redistribution of states. We show that the internal state of the ion is sensitive to collisional coherences and the wake field. The results of the full simulations are found to be in good agreement with experimental data

[en] We present a review of our study of interactions of plasma particles (atoms, molecules) with hydrogenated amorphous carbon surfaces typical of plasma-facing divertor tiles and deposited layers in magnetic-fusion reactors. Our computer simulations of these processes are based on classical molecular dynamics simulations, using the best currently available multibody bond-order hydrocarbon potentials. Our research in this field has been focused on the chemical sputtering of carbon surfaces at low impact energies, the most complex of the plasma-surface interactions (PSI). Close collaboration with beam-surface and plasma-surface experiments provides not only theoretical support for the experiments, but also builds suitable benchmarks for our methods and codes, enabling production of theoretical plasma-surface data with increased reliability

[en] The main topics of this proceedings were: (1) Energy loss of particles at surfaces; (2) Scattering of atoms, ions, molecules and clusters; (3) Charge exchange between particles and surfaces; (4) Ion induced desorption, electronic and kinetic sputtering; (5) Defect formation, surface modification and nanostructuring; (6) Electron, photon and secondary ion emission due to particle impact on surfaces; (7) Sputtering, fragmentation, cluster and ion formation in SIMS and SNMS; (8) Cluster/molecular and highly charged ion beams; and (9) Laser induced desorption.

[en] We perform molecular dynamics simulations of the chemical sputtering of deuterated amorphous carbon surfaces irradiated by low energy deuterium atoms and molecules (<30 eV/D). Particular attention was paid to the proper preparation of the surfaces, as well as to the internal (rovibrational) state of impinging molecules. Sputtered hydrocarbons are analyzed with respect to their mass, kinetic energy, and angular distribution. The sputtering yields are in good agreement with recent experimental results

[en] The bombardment of both graphite and deuterated amorphous carbon surfaces with 20 eV D atoms has been performed using molecular dynamics simulation. The primary purpose of these simulations is to determine whether the eventual state of the surface, once it has reached a steady state, is independent of the starting structure. It is found that while independently realized amorphous carbon structures give rise to similar impact-modified surfaces, the graphitic surface evolves towards a somewhat different structure. Including or neglecting a realistic treatment of the nonbonded interactions in the graphite bombardment does not result in large differences in the impact-modified structure, although the penetration depth is considerably less when nonbonded interactions are included.

[en] Atoms in high-lying Rydberg states with large values of the principal quantum number n, n (ge) 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