Electron-ion recombination of Si IV forming Si III: Storage-ring measurement and multiconfiguration Dirac-Fock calculations

TL;DR

This study combines storage-ring measurements and multiconfiguration Dirac-Fock calculations to accurately determine the electron-ion recombination rates of Si IV forming Si III, crucial for astrophysical plasma modeling.

Contribution

It provides the first comprehensive comparison of experimental and theoretical DR rate coefficients for Si IV, enhancing the accuracy of plasma modeling data.

Findings

Experimental DR rates agree with theoretical calculations within uncertainties.

New data improve the accuracy of plasma modeling for astrophysical environments.

Comparison with previous results shows significant improvements in rate coefficient precision.

Abstract

The electron-ion recombination rate coefficient for Si IV forming Si III was measured at the heavy-ion storage-ring TSR. The experimental electron-ion collision energy range of 0-186 eV encompassed the 2p(6) nl n'l' dielectronic recombination (DR) resonances associated with 3s to nl core excitations, 2s 2p(6) 3s nl n'l' resonances associated with 2s to nl (n=3,4) core excitations, and 2p(5) 3s nl n'l' resonances associated with 2p to nl (n=3,...,infinity) core excitations. The experimental DR results are compared with theoretical calculations using the multiconfiguration Dirac-Fock (MCDF) method for DR via the 3s to 3p n'l' and 3s to 3d n'l' (both n'=3,...,6) and 2p(5) 3s 3l n'l' (n'=3,4) capture channels. Finally, the experimental and theoretical plasma DR rate coefficients for Si IV forming Si III are derived and compared with previously available results.