Fine-structure electron-impact excitation of Ne$^{+}$ and Ne$^{2+}$ for low temperature astrophysical plasmas

TL;DR

This paper calculates electron-impact excitation collision strengths for Ne$^{+}$ and Ne$^{2+}$ ions at very low temperatures relevant to astrophysical plasmas, using multiple theoretical methods to estimate uncertainties.

Contribution

It provides new low-temperature collision data for Ne ions using diverse computational approaches, assessing uncertainties and resonance sensitivities.

Findings

Good agreement with previous high-temperature calculations.

Estimated uncertainties based on different theoretical methods.

Sensitivity analysis of resonance positions and atomic structure.

Abstract

Collision strengths for electron-impact of fine-structure level excitation within the ground term of Ne$^{+}$ and Ne$^{2+}$ are calculated using the Breit-Pauli, Intermediate Coupling Frame Transformation, and DARC $R$-matrix methods. Maxwellian-averaged effective collision strengths and excitation rate coefficient qij are presented for each. The application of the current calculations is to very low temperature astrophysical plasmas, thus we examine the sensitivity of the effective collision strengths down to 10 K. The use of the various theoretical methods allows us to place estimated uncertainties on the recommended effective collision strengths. We also investigate the sensitivity of the collision strengths to the resonance positions and underlying atomic structure. Good agreement is found with previous R-matrix calculations at higher temperature.