Petascale Computations for Large-Scale Atomic and Molecular Collisions

Abstract

Petaflop architectures are currently being utilized efficiently to perform large scale computations in Atomic, Molecular and Optical Collisions. We solve the Schrödinger or Dirac equation for the appropriate collision problem using the R-matrix or R-matrix with pseudo-states approach. We briefly outline the parallel methodology used and implemented for the current suite of Breit-Pauli and DARC codes. Various examples are shown of our theoretical results compared with those obtained from Synchrotron Radiation facilities and from Satellite observations. We also indicate future directions and implementation of the R-matrix codes on emerging GPU architectures.

Photoionization of tungsten ions: experiment and theory for ${{\rm{W}}}^{2+}$ and ${{\rm{W}}}^{3+}$

“…Recent modifications to the Dirac-Atomic-R-matrix-Codes (DARC) [28][29][30][31] have allowed large scale photoionization cross section calculations to be made on heavy complex systems of prime interest to astrophysics and plasma applications in a timely manner. These codes are presently running on a variety of parallel high performance computing architectures world wide [32,33].…”

Single-photon single ionization of W+ions: experiment and theory

“…An efficient parallel version [26] of the DARC [27][28][29] suite of codes was applied which has been developed [30][31][32] to address electron and photon interactions with atomic systems providing for hundreds of levels and thousands of scattering channels. These codes are presently running on a variety of parallel high performance computing architectures world wide [33,34]. Recently, DARC calculations on photoionization of trans-Fe elements were carried out for Se + , Kr + , Xe + , and Xe 7+ ions [20,31,32,35] showing suitable agreement with high resolution ALS measurements.…”

PAMOP Project: Computations in Support of Experiments and Astrophysical Applications

“…It allows one to provide atomic data in the absence of experiment, and for that purpose takes advantage of the linear algebra libraries available on most architectures. 46.193 Further developments of the dipole codes benefit from similar developments made to the existing excitation R-matrix codes [6,7,8,9]. In Table 1 we show typical timings required in the determination of the photoionization cross section results for W 2+ ions, for the J=1 even scattering symmetry.…”

“…An efficient parallel version [10,11] of the DARC [25,24,26] suite of codes continues to be developed and applied to address electron and photon interactions with atomic systems, providing for hundreds of levels and thousands of scattering channels. These codes are presently running on a variety of parallel high performance computing architectures world wide [7,8,9] tions and detailed energy scans were measured over an energy range from about 20 eV to 90 eV at a bandwidth of 100 meV. Broad peak features with widths typically around 5 eV have been observed with almost no narrow resonances present in the investigated energy range.…”