Current Status and Developments of the Atomic Database on Rare-Earths at Mons University (DREAM)

Pascal Quinet,Patrick Palmeri

doi:10.3390/atoms8020018

Abstract

The main purpose of the Database on Rare Earths At Mons University (DREAM) is to provide the scientific community with updated spectroscopic parameters related to lanthanide atoms (Z = 57–71) in their lowest ionization stages. The radiative parameters (oscillator strengths and transitions probabilities) listed in the database have been obtained over the past 20 years by the Atomic Physics and Astrophysics group of Mons University, Belgium, thanks to a systematic and extensive use of the pseudo-relativistic Hartree-Fock (HFR) method modified for taking core-polarization and core-penetration effects into account. Most of these theoretical results have been validated by the good agreement obtained when comparing computed radiative lifetimes and accurate experimental values measured by the time-resolved laser-induced fluorescence technique. In the present paper, we report on the current status and developments of the database that gathers radiative parameters for more than 72,000 spectral lines in neutral, singly-, doubly-, and triply-ionized lanthanides.

Highlights

The atomic structures and radiative properties characterizing the lowest ionization stages of lanthanide elements, from La (Z = 57) to Lu (Z = 71), have been the subject of many experimental and theoretical investigations during the last years
The cumulative numbers of relevant papers published over the last decades are reported in Figures 1 and 2, respectively. These figures are the result of a steady increase of publications since the 1950s, demonstrating the growing interest for the atomic data characterizing such heavy atomic species. This is mainly due to the fact that the remarkably rich spectra arising from lanthanide ions provide an essential source of information for the development of other fields, mainly in astrophysics and the lighting industry
In this latter, described in detail in many of our previous papers, the largest part of the intravalence correlation is represented within a configuration interaction scheme, i.e., by explicitly including a set of electronic configurations in the physical model, while core-valence correlation is approximated by a core-polarization (CPOL) model potential depending on two parameters, namely the dipole polarizability, αd, of the ionic core, for which numerical values can be found in the literature, and the cut-off radius, rc, that is arbitrarily chosen as a measure of the size of the ionic core

Summary

Introduction

The largest remaining uncertainty in kilonova emission relates to missing information about the wavelength dependent opacity of the ejecta, mostly because of the lack of relevant atomic data for the lowest ionization stages of lanthanides [14,15]. Because of their unusual luminescent properties, triply ionized lanthanide atoms play an important role in photonics, laser physics, biotechnology, medical diagnostics, and lighting industry, see, e.g., [16,17,18,19]. We briefly remind how these radiative parameters were determined, we present an overview of the current status and developments of DREAM, and we give some remarkable examples of use of the data available in this database

Atomic Structure and Radiative Rate Calculations

Comparisons with Experimental Data

Current Status and Developments of the DREAM Database

Some Examples of Uses of Atomic Data from DREAM

Findings

Conclusions