Publications (23)
Electron-impact ionization of atomic hydrogen at 2 eV above threshold
Igor Bray
The convergent close-coupling method is applied to the calculation of fully differential cross sections for ionization of atomic hydrogen by 15.6 eV electrons. We find that even at…
Photoionization from the ground and excited vibrational states of H+2 and its deuterated isotopologues
Adam Singor, Liam H. Scarlett, Mark C. Zammit +2
Photoionization cross sections and rate coefficients have been calculated for all bound vibrational levels of the 1s state of H, HD, and D$_{2}^{+}…
Different escape modes in two-photon double ionization of helium
A. S. Kheifets, I. A. Ivanov, Igor Bray
The quadrupole channel of two-photon double ionization of He exhibits two distinctly different modes of correlated motion of the photoelectron pair. The mode associated with the ce…
Ultraviolet H luminescence in molecular clouds induced by cosmic rays
Marco Padovani, Daniele Galli, Liam H. Scarlett +5
Galactic cosmic rays (CRs) play a crucial role in ionisation, dissociation, and excitation processes within dense cloud regions where UV radiation is absorbed by dust grains and ga…
Excitation of molecular hydrogen by cosmic-ray protons
Marco Padovani, Daniele Galli, Corey T. Plowman +4
Low-energy cosmic rays ( GeV) are responsible for the ionisation and heating of molecular clouds. While the role of supra-thermal electrons produced in the ionisation…
Calculations for electron-impact excitation and ionization of beryllium
Oleg Zatsarinny, Klaus Bartschat, Dmitry V. Fursa +1
The B-spline R-matrix and the convergent close-coupling methods are used to study electron collisions with neutral beryllium over an energy range from threshold to 100 eV. Coupling…
Convergence of two-center expansions in positron-hydrogen collisions
Alisher S. Kadyrov, Igor Bray
The positron-hydrogen atom scattering system is considered within the S-wave model. Convergence in the elastic scattering, excitation, ionization, and positronium formation channel…
A New Approach to Modeling Line Shapes with Quasi-H Satellites in Stellar Atmospheres
Jackson R. White, Thomas A. Gomez, Mark C. Zammit +6
Theoretical spectral line shapes describe the distribution of opacity due to bound electronic transitions in hot dense plasmas and are used to fit emergent spectra from many astrop…
Isotopic and vibrational-level dependence of H dissociation by electron impact
Liam H. Scarlett, Dmitry V. Fursa, Jack Knol +2
The low-energy electron-impact dissociation of molecular hydrogen has been a source of disagreement between various calculations and measurements for decades. Excitation of the gro…
Spin-resolved electron-impact ionization of lithium
Igor Bray, Justin Beck, Chris Plottke
Electron-impact ionization of lithium is studied using the convergent close-coupling (CCC) method at 25.4 and 54.4 eV. Particular attention is paid to the spin-dependence of the io…
Experimental Validation of Collision-Radiation Dataset for Molecular Hydrogen in Plasmas
Keisuke Fujii, Keiji Sawada, Kuzmin Arseniy +7
Quantitative spectroscopy of molecular hydrogen has generated substantial demand, leading to the accumulation of diverse elementary-process data encompassing radiative transitions,…
Convergent calculations of double ionization of helium: from (,2e) to (e,3e) processes
A. S. Kheifets, Igor Bray
The first absolute (e,3e) measurements, by Lahmam-Bennani et al [Phys. Rev. A {\bf 59}, 3548 (1999)], have been recently approximately reproduced by Berakdar [Phys. Rev. Lett. {\bf…
Collisional-radiative data for tokamak disruption mitigation modeling
Prashant Sharma, Christopher J. Fontes, Dmitry V. Fursa +6
Effective tokamak disruption mitigation is crucial for ensuring the safety and integrity of fusion power reactors. Accurate collisional-radiative (CR) modeling of a radiative plasm…
Enhancements of Electron-Atom Collisions due to Pauli Repulsion in Neutron-Star Magnetic Fields
Thomas Gomez, Mark Zammit, Igor Bray +2
Neutron star surfaces and atmospheres are unique environments that sustain the largest-known magnetic fields in the universe. Our knowledge of neutron star material properties, inc…
Cosmic rays in molecular clouds probed by H rovibrational lines -- Perspectives for the James Webb Space Telescope
Marco Padovani, Shmuel Bialy, Daniele Galli +7
Cosmic rays (CRs) at sub-TeV energies play a fundamental role in the chemical and dynamical evolution of molecular clouds, as they control the ionisation, dissociation, and excitat…
Attosecond Time Delays at Cooper Minima in Valence-Shell Photoionization of Alkali and Alkaline-Earth Metal Atoms
Adam J. C. Singor, Dmitry V. Fursa, Igor Bray +1
Ji \etal [New J. Phys. {\bf 26}, 093014 (2024)] established a direct link between the photoionization cross section and the attosecond time delay near Cooper minima (CM) in the val…
Calculation of the free-free transitions in the electron-hydrogen scattering S-wave model
Chris Plottke, Igor Bray
The S-wave model of electron-hydrogen scattering is evaluated using the convergent close-coupling method with an emphasis on scattering from excited states including an initial sta…
A study of cross sections for excitation of pseudostates
Igor Bray
Using the electron-hydrogen scattering Temkin-Poet model we investigate the behavior of the cross sections for excitation of all of the states used in the convergent close-coupling…
Quantum-mechanical calculation of Stark widths of Ne VII n=3, transitions
Yuri V. Ralchenko, Hans R. Griem, Igor Bray +1
The Stark widths of the Ne VII 2s3s-2s3p singlet and triplet lines are calculated in the impact approximation using quantum-mechanical Convergent Close-Coupling and Coulomb-Born-Ex…
Non-LTE analysis of K I in late-type stars
Henrique Reggiani, Anish M. Amarsi, Karin Lind +7
Older GCE models predict [K/Fe] ratios as much as 1 dex lower than those inferred from stellar observations. Abundances of potassium are mainly based on analyses of the 7698 r…
Stark Broadening of the B III 2s-2p Lines
Hans R. Griem, Yuri V. Ralchenko, Igor Bray
We present a quantum-mechanical calculation of Stark line widths from electron-ion collisions for the , lambda = 2066 and 2067 A, resonance transitions in B…
Electron-impact ionization of atomic hydrogen from near threshold to high energies
Igor Bray
Application of the convergent close-coupling (CCC) method to electron-impact ionization of the ground state of atomic hydrogen is considered at incident energies of 15.6, 17.6, 20,…
A Science Gateway for Atomic and Molecular Physics
Barry I. Schneider, Klaus~Bartschat, Oleg Zatsarinny +7
We describe the creation of a new Atomic and Molecular Physics science gateway (AMPGateway). The gateway is designed to bring together a subset of the AMP community to work collect…