Energy levels, radiative rates and electron impact excitation rates for transitions in Be-like Ti XIX

TL;DR

This paper presents detailed calculations of energy levels, radiative rates, and electron impact excitation rates for Be-like Ti XIX, emphasizing the importance of resonances and comparing results from different computational methods.

Contribution

The study provides comprehensive atomic data for Ti XIX using relativistic calculations and highlights the significance of resonance effects in excitation rates.

Findings

Resonance effects significantly influence excitation rates.

Comparison shows discrepancies between DARC and FAC results.

Data covers a wide temperature range up to 10^7.7 K.

Abstract

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in Be-like Ti XIX. The GRASP (General-purpose Relativistic Atomic Structure Package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths and subsequently the excitation rates, the Dirac Atomic R-matrix Code (DARC) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 98 levels of the n <= 4 configurations. Additionally, theoretical lifetimes are listed for all 98 levels. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 10**7.7 K. Comparisons are made with similar data obtained from the Flexible Atomic Code (FAC) to highlight the importance of resonances, included in calculations with DARC, in the determination of effective collision strengths. Discrepancies between the collision strengths from DARC and FAC, particularly for forbidden transitions, are also discussed.