Related papers: Self-consistent ab initio calculations for photoio…
A general formulation is developed to demonstrate that atomic autoionizing (AI) resonances are broadened and shifted significantly due to plasma effects across bound-free continua. The theoretical and computational method presented accounts…
The photoionization spectrum of an atom in a magnetic field is calculated by combining R-matrix propagation with local adiabatic basis expansions. This approach considerably increases the speed and the energy range over which calculations…
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…
An alternative method is introduced to solve a simple two-dimensional models describing vibrational excitation and dissociation processes during the electron-molecule collisions. The model works with one electronic and one nuclear degree of…
A general formulation is employed to study and quantitatively ascertain the effect of plasma broadening of {\it intrinsic} autoionizing (AI) resonances in photoionization cross sections. In particular, R-matrix data for iron ions described…
Reliably interpreting spectra from electron-ionized cosmic plasmas requires accurate ionization balance calculations for the plasma in question. However, much of the atomic data needed for these calculations have not been generated using…
We report the first unambiguous observational evidence of Rydberg Enhanced Recombination (RER), a potentially important recombination mechanism that has hitherto been unexplored in low-temperature photoionized plasmas. RER shares…
Extensive resonance structures are manifest in R-Matrix (RM) calculations. However, there exist a large number of highly excited electronic configurations that may contribute to background non-resonant bound-free opacity in high-temperature…
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 present R-matrix calculations of photoabsorption and photoionization cross sections across the K edge of the Li-like to Ca-like ions stages of Ni. Level-resolved, Breit-Pauli calculations were performed for the Li-like to Na-like stages.…
For photoionized plasmas, electron energy-loss rates due to radiative recombination (RR) are required for thermal equilib- rium calculations, which assume a local balance between the energy gain and loss. While many calculations of total…
A review of a renewed effort to recalculate astrophysical opacities using the R-Matrix method is presented. The computational methods and new extensions are described. Resulting enhancements found in test calculations under stellar interior…
We present multi-configuration Breit-Pauli AUTOSTRUCTURE calculations of distorted-wave photoionization (PI) cross sections, and total and partial final-state resolved radiative recombination (RR) and dielectronic recombination (DR) rate…
The effect of autoionizing resonances in atomic systems and processes is reviewed. Theoretical framework for treating resonances in the coupled channel approximation using the R-matrix method, as well as approximations related to plasma…
Observations are beginning to constrain the history of the epoch of reionization (EoR). Modeling the reionization process is indispensable to interpret the observations, to infer the properties of ionizing sources, and to probe the various…
We present a new extension of the UKRmol electron-molecule scattering code suite, which allows one to compute ab initio photoionization and photorecombination amplitudes for complex molecules, resolved both on the molecular alignment…
Absolute cross sections for the K-shell photoionization of ground-state Li-like carbon [C$^{3+}$(1s$^2$2s $^2$S)] ions were measured by employing the ion-photon merged-beams technique at the Advanced Light Source. The energy ranges…
We formulate a computationally efficient time-independent method based on the multi-electron molecular R-matrix formalism. This method is used to calculate transition matrix elements for the multi-photon ionization of atoms and molecules…
Recent R-matrix calculations claim to produce a significant enhancement in the opacity of Fe XVII due to atomic core excitations [S. N. Nahar & A.K. Pradhan, Phys. Rev. Letters 116, 235003 (2016), arXiv:1606.02731] and assert that this…
We present the first detailed ab initio quantum mechanical calculations for total and state-specific recombination rate coefficients for e + Ni III --> Ni II. These rates are obtained using a unified treatment for total electron-ion…