MCDHF and RCI calculations of energy levels, lifetimes, and transition rates in Si III and Si IV

TL;DR

This paper provides detailed multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations for energy levels, lifetimes, and transition rates in Si III and Si IV, aiding astrophysical plasma analysis.

Contribution

It extends and improves previous calculations for Si III and Si IV, especially for Si IV, with extensive state coverage and better agreement with experimental data.

Findings

Good agreement with experimental energies and transition data

Identified deviations from NIST database for certain Rydberg series

Enhanced understanding of silicon ion spectra for astrophysics

Abstract

We present extensive multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations including 106 states in doubly ionized silicon (Si III) and 45 states in triply ionized silicon (Si iv), which are important for astrophysical determination of plasma properties in different objects. These calculations represents an important extension and improvement of earlier calculations especially for Si IV. The calculations are in good agreement with available experiments for excitation energies, transition properties, and lifetimes. Important deviations from the NIST-database for a selection of perturbed Rydberg series are discussed in detail.