Autoionization in time-dependent density-functional theory

Kapoor, Varun

doi:10.1103/physreva.93.063408

Cited by 15 publications

(13 citation statements)

References 32 publications

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“…In particular, Auger transitions are not expected to be accounted for. [22,23] However, this is not a major restriction in case of the present simulations, because Merino et al [24] have concluded from their study using a model Hamiltonian that at the low H + kinetic energies considered here (below keV) the charge transfer is dominated by resonant processes. Finally, we note that the TDDFT-MD simulations we present below refer to the valence electrons only.…”

Section: Tddft Simulations Of Charge Transfer and Ion Stoppingmentioning

confidence: 84%

“…[30] It is argued that no electron-electron relaxation (Auger effect) occurs when the present adiabatic XC-functionals are employed. [22,23] Theoretical work on the He + /Al system shows that in case of the projectile velocity range applied here, the Auger channel is the relevant one in order to be able to describe the experiment. [52][53][54][55] First test calculations within the framework described above for a He + ion (E kin = 2 H) incident on an Al(111) surface, confirm that Auger processes do not show in the calculations performed using an adiabatic GGA XC-functional.…”

Section: 2mentioning

confidence: 92%

“…In case of H + incident on the Al-cluster in the present calculation the initial configuration is spin-unpolarized and there is no term in the Hamiltonian that could break this symmetry during time evolution. [22,23] Theoretical work on the He + /Al system shows that in case of the projectile velocity range applied here, the Auger channel is the relevant one in order to be able to describe the experiment. [48] For the model-Hamiltonian calculations, the problem of correlation has been approached using, for example, as approximation for the correlation in multiple-level systems U → ∞.…”

Section: 2mentioning

confidence: 99%

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Time‐dependent simulation of ion stopping: Charge transfer and electronic excitations

Schlünzen

Balzer

Bönitz

et al. 2019

Contributions to Plasma Physics

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The energy loss of charged particles in matter has been studied for many decades, both, analytically and via computer simulations. While the regime of high projectile energies is well understood, low energy stopping in solids is more challenging due to the importance of non-adiabatic effects and electronic correlations. Here we consider two problems: the charge transfer between substrate and projectile and the role of electronic correlations, specifically formation of doubly occupied lattice sites in the material during the stopping process. The former problem is treated by time-dependent density functional theory simulations and the latter by non-equilibrium Green functions.

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Section: Tddft Simulations Of Charge Transfer and Ion Stoppingmentioning

confidence: 84%

Section: 2mentioning

confidence: 92%

Section: 2mentioning

confidence: 99%

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Time‐dependent simulation of ion stopping: Charge transfer and electronic excitations

Schlünzen

Balzer

Bönitz

et al. 2019

Contributions to Plasma Physics

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“…182, when applying the ALDA for the XC potential in TDDFT doubly excited configurations are not accounted for. Based on the calculation of an exact XC-potential, V. Kapoor [183] has concluded that autoionization requires inclusion of memory effects in the XC-potential, which displays a rather complicated structure. When calculating e.g.…”

Section: B Time-dependent Dftmentioning

confidence: 99%

Towards an integrated modeling of the plasma-solid interface

Bönitz

Filinov

Abraham

et al. 2019

Front. Chem. Sci. Eng.

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Solids facing a plasma are a common situation in many astrophysical systems and laboratory setups. Moreover, many plasma technology applications rely on the control of the plasma-surface interaction, i.e. of the particle, momentum and energy fluxes across the plasma-solid interface. However, presently often a fundamental understanding of them is missing, so most technological applications are being developed via trial and error. The reason is that the physical processes at the interface of a low-temperature plasma and a solid are extremely complex, involving a large number of elementary processes in the plasma, in the solid as well as fluxes across the interface. An accurate theoretical treatment of these processes is very difficult due to the vastly different system properties on both sides of the interface: quantum versus classical behavior of electrons in the solid and plasma, respectively; as well as the dramatically differing electron densities, length and time scales. Moreover, often the system is far from equilibrium. In the majority of plasma simulations surface processes are either neglected or treated via phenomenological parameters such as sticking coefficients, sputter rates or secondary electron emission coefficients. However, those parameters are known only in some cases and with very limited accuracy. Similarly, while surface physics simulations have often studied the impact of single ions or neutrals, so far, the influence of a plasma medium and correlations between successive impacts have not been taken into account. Such an approach, necessarily neglects the mutual influences between plasma and solid surface and cannot have predictive power.In this paper we discuss in some detail the physical processes a the plasma-solid interface which brings us to the necessity of coupled plasma-solid simulations. We briefly summarize relevant theoretical methods from solid state and surface physics that are suitable to contribute to such an approach and identify four methods. The first are mesoscopic simulations such as kinetic Monte Carlo (KMC) and molecular dynamics (MD) that are able to treat complex processes on large scales but neglect electronic effects. The second are quantum kinetic methods based on the quantum Boltzmann equation that give access to a more accurate treatment of surface processes using simplifying models for the solid. The third approach are ab initio simulations of surface process that are based on density functional theory (DFT) and time-dependent DFT. The fourths are nonequilibrium Green functions that able to treat correlation effects in the material and at the interface. The price for the increased quality is a dramatic increase of computational effort and a restriction to short time and length scales. We conclude that, presently, none of the four methods is capable of providing a complete picture of the processes at the interface. Instead, each of them provides complementary information, and we discuss possible combinations. PACS numbers:

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“…The described grid is partitioned into different sections, figure 1(a). This partitioning technique has been successfully implemented previously in several theoretical studies of the ionization from the ground state of small atoms and molecules [32][33][34][35][36][37][38]. Time-dependent changes in the electronic density in each of the grid segments, I to IX in figure 1(a), indicate dynamical effects caused by the interaction with an external laser field.…”

Section: P Gmentioning

confidence: 99%

Strong-field-induced single and double ionization dynamics from single and double excitations in a two-electron atom

et al. 2020

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Two-electron dynamics of an excited model atom interacting with moderately strong laser fields is analyzed in the time domain. We solve the time-dependent Schrödinger equation (TDSE) for two electrons confined to the same one-dimensional configuration space, accounting also for the electronelectron interaction. The computational method allows direct access to the time-dependent population of the relevant atomic states during and right after the interaction with a near-infrared (NIR) laser pulse. We compare the ionization dynamics of singly excited states and doubly excited states. We find that doubly-excited initial states exhibit enhanced double ionization yield, with non-trivial dynamics including contributions from direct and sequential processes, while the electrons leave the atom either back-to-back or in the same direction.

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Autoionization in time-dependent density-functional theory

Cited by 15 publications

References 32 publications

Time‐dependent simulation of ion stopping: Charge transfer and electronic excitations

Time‐dependent simulation of ion stopping: Charge transfer and electronic excitations

Towards an integrated modeling of the plasma-solid interface

Strong-field-induced single and double ionization dynamics from single and double excitations in a two-electron atom

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