Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Kr XXXV

TL;DR

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

Contribution

The study provides comprehensive atomic data for Kr XXXV using relativistic codes, including comparisons with other methods to assess accuracy and resonance effects.

Findings

Resonance effects significantly influence excitation rates.

Differences observed between DARC and FAC results, especially for forbidden transitions.

Discrepancies noted with earlier semi-relativistic data across various temperatures.

Abstract

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Kr XXXV. 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 49 levels. Additionally, theoretical lifetimes are listed for all 49 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**8.1 K. Comparisons are made with similar data obtained with the Flexible Atomic Code (FAC) to assess the accuracy of the results and to highlight the importance of resonances, included in calculations with DARC, in the determination of effective collision strengths. Differences between the collision strengths from DARC and FAC, particularly for forbidden transitions, are also discussed. Finally, discrepancies between the present results of effective collision strengths from the {\sc darc} code and earlier semi-relativistic $R$-matrix data are noted over a wide range of electron temperatures for many transitions of Kr XXXV.