  Uncertainties in atomic models will introduce noticeable additional
systematics in calculating the flux of weak dielectronic recombination (DR)
satellite lines, affecting the detection and flux measurements of other weak
spectral lines. One important example is the Ar XVII He-beta DR, which is
expected to be present in emission from the hot intracluster medium (ICM) of
galaxy clusters and could impact measurements of the flux of the 3.5 keV line
that has been suggested as a secondary emission from a dark matter interaction.
We perform a set of experiments using the Lawrence Livermore National
Laboratory's electron beam ion trap (EBIT-I) and the X-Ray Spectrometer quantum
calorimeter (XRS/EBIT), to test the Ar XVII He-beta DR origin of the 3.5 keV
line. We measured the X-ray emission following resonant DR onto helium-like and
lithium-like Argon using EBIT-I's Maxwellian simulator mode at a simulated
electron temperature of Te=1.74 keV. The measured flux of the Ar XVII He-beta
DR lined is too weak to account for the flux in the 3.5 keV line assuming
reasonable plasma parameters. We, therefore, rule out Ar XVII He-beta DR as a
significant contributor to the 3.5 keV line. A comprehensive comparison between
the atomic theory and the EBIT experiment results is also provided.
