ATOM - System for Studying the Structure of Atoms

Abstract

Atomic structure and its study in relationship with radiation are key to the progress of modern physics and associated computational sciences. The growing complexity of atomic systems has led over time to the need to develop effective computational methods that are capable of accurately capturing many-electron interactions and other related processes. The ATOM system is a unified system of computations that attempts to deal with these issues by combining established theoretical methods, such as the Hartree-Fock approximation and the random-phase approximation with exchange.
This mini review gives an overview of the ATOM system, its architecture, its computational capabilities, and its use in modeling atomic processes including photoionization, electron scattering, and decay processes. The hierarchical structure and modular nature of the system allow flexibility in treating a large variety of atomic and ionic interactions and is computationally efficient.
Moreover, the review explains how the ATOM system has evolved over time, how it has helped to support large-scale computational experiments, and how it has helped to reconcile theoretical predictions with experimental results. With all its merits, some aspects of improvement, such as accessibility and integration with contemporary computational environments are also pointed out.
In general, the ATOM system remains an effective instrument of theoretical atomic physics, providing information about the complicated phenomena of atoms and facilitating further studies in the area.
The ATOM system, described in [1-4], contains a large number of programs necessary for calculating atomic processes, including photoionization, Auger and radiative decays, elastic and inelastic scattering, and many others. Calculations are performed within the Hartree-Fock (HF) approximation and the Random-Phase Approximation with Exchange (RPAE), which takes into account the many-electron correlations important in these processes. The ATOM system can be used to perform perturbation theory calculations.