J
Joshua J. Kas
Researcher at University of Washington
Publications - 75
Citations - 3307
Joshua J. Kas is an academic researcher from University of Washington. The author has contributed to research in topics: Scattering & Ab initio. The author has an hindex of 25, co-authored 68 publications receiving 2698 citations. Previous affiliations of Joshua J. Kas include SLAC National Accelerator Laboratory.
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Parameter-free calculations of X-ray spectra with FEFF9
TL;DR: It is described how approximations can be replaced by efficient ab initio models including a many-pole model of the self-energy, inelastic losses and multiple-electron excitations; a linear response approach for the core hole; and a Lanczos approach for Debye-Waller effects.
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Ab initio theory and calculations of X-ray spectra
TL;DR: Rehr et al. as discussed by the authors proposed ab initio calculations of the dielectric function over a broad spectrum yield system dependent self-energies and mean-free paths, as well as intrinsic losses due to multi-electron excitations.
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Bethe-Salpeter equation calculations of core excitation spectra.
TL;DR: A hybrid approach for Bethe-Salpeter equation (BSE) calculations of core excitation spectra, including x-ray absorption, electron energy loss spectra (EELS), and nonresonant inelastic x-rays scattering (NRIXS) is presented.
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Efficient implementation of core-excitation Bethe Salpeter equation calculations
Keith Gilmore,Keith Gilmore,John Vinson,Eric L. Shirley,David Prendergast,Chaitanya Das Pemmaraju,Joshua J. Kas,Fernando D. Vila,John J. Rehr +8 more
TL;DR: Improvements include the implementation of optimal basis functions that reduce the cost of the initial DFT calculations, more complete parallelization of the screening calculation and of the action of the BSE Hamiltonian, and various memory reductions.
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Valence Electron Photoemission Spectrum of Semiconductors: Ab Initio Description of Multiple Satellites
Matteo Guzzo,Giovanna Lani,Francesco Sottile,Pina Romaniello,Matteo Gatti,Joshua J. Kas,John J. Rehr,Mathieu G. Silly,Fausto Sirotti,Lucia Reining +9 more
TL;DR: This work compares experimental high energy photoemission spectra with GW calculations, and proposes an approximation to the functional differential equation that determines the exact one-body Green's function, whose solution has an exponential form.