Related papers: Angular distributions in two-colour two-photon ion…
We present a fully {\it ab initio}, non-perturbative, time-dependent approach to describe single and double ionization of helium by proton and antiproton impact. A flexible and accurate finite-element discrete-variable-representation is…
Attosecond photoionisation time delays reveal information about the potential energy landscape an outgoing electron wavepacket probes upon ionisation. In this study we experimentally quantify, for the first time, the dependence of the time…
Extracting single photoionization time delays associated with atomic (or molecular) species from attosecond time scale two-photon experiments usually relies on the theoretical description of continuum-continuum transitions. The available…
We investigate the resonance-enhanced few-photon ionization of atomic lithium by linearly polarized light whose frequency is tuned near the 2s-2p transition. Considering the direction of light polarization orthogonal to the quantization…
In a previous article, with a new code designed for a photoionized thick hot medium using a full transfer treatment of both lines and continuum, we have studied the He-like emission of a medium photoionized by an X-ray source. We considered…
The double-slit interference in single-photon ionization of the diatomic molecular ion $\mathrm{H}_2^+$ is theoretically studied beyond the dipole approximation. Via simulating and comparing the interactions of the prealigned…
During multi-photon ionization of an atom it is well understood how the involved photons transfer their energy to the ion and the photoelectron. However, the transfer of the photon linear momentum is still not fully understood. Here, we…
We calculate the photoionization with excitation-to photoionization ratios for atomic helium and heliumlike ions at intermediate values of the photon energies. The final state interactions between the electrons are included in the lowest…
Photoelectron angular distributions following the non-resonant two-photon K-shell ionization of neutral atoms are studied theoretically. Using the independent particle approximation and relativistic second-order perturbation theory, the…
We review different computational methods for the calculation of photoelectron spectra and angular distributions of atoms and molecules when excited by laser pulses using time-dependent density-functional theory (TDDFT) that are suitable…
When an atom or molecule absorbs a high-energy photon, an electron is emitted with a well-defined energy and a highly-symmetric angular distribution, ruled by energy quantization and parity conservation. These rules seemingly break down…
We describe a numerical method that simulates the interaction of the helium atom with sequences of femtosecond and attosecond light pulses. The method, which is based on the close-coupling expansion of the electronic configuration space in…
The success of the R-matrix with pseudo-state (RMPS) method to model single photoionization processes, benchmarked against dedicated synchrotron light source measurements, is exploited and extended to investigate, single photon double…
We consider the calculations of photoionization spectra and core resonances of open-shell systems using range-separated time-dependent density-functional theory. Specifically, we use the time-dependent range-separated hybrid (TDRSH) scheme,…
We present a new approach to constrain the spectral energy distribution of the intergalactic UV background observationally by studying metal absorption systems. We study single-component metal line systems exhibiting various well-measured…
Wavefunction-splitting or mask method, widely used in the non-relativistic calculations of the photoelectron angular distributions, is extended to the relativistic domain within the dipole approximation. Since the closed-form expressions…
The single ionization of noble gas atoms by the combined action of XUV attopulses and an infrared laser field is theoretically investigated by means of a non-perturbative model that under certain approximations gives closed-form expressions…
We employ the Kramers-Henneberger Hamiltonian for time-independent calculations of multi-photon ionization of atoms with one and two electrons. As compared to the electromagnetic interaction in the length and velocity gauges, the presently…
Theoretical approaches to the photoionization of few-electron atoms are discussed. These include nonequilibrium Greens functions and wave function based approaches. In particular, the Multiconfiguration Time-Dependent Hartree-Fock method is…
A theoretical investigation of photoabsorption and photoionization of Fe^{14+} extending beyond an earlier frame transformation R-matrix implementation is performed using a fully-correlated, Breit-Pauli R-matrix formulation including both…