Electron-impact widths and shifts of SrII lines in ultracold neutral plasmas

Abstract

In this paper, we report on relativistic quantum-mechanical calculations of electron-impact linewidths and line shifts in singly ionized strontium ions in ultracold neutral plasmas. We have used the Dirac $R$-matrix methods to solve ($N+1$)-electron colliding systems and to generate the required scattering matrices. Calculated linewidths and line shifts at an electron density ${10}^{17}\phantom{\rule{0.16em}{0ex}}{\text{cm}}^{\ensuremath{-}3}$ and electron temperatures (several electronvolts) agree well with other theoretical calculations and are closer to the experimental observations. Our theoretical findings of linewidths and line shifts are almost twice as large as the earlier calculations for the particular selected plasma conditions. This work develops these quantum-mechanical procedures and applies them to the emission from ultracold neutral plasmas.