N. P. ABEL, Department of Physics, University of Cincinnati, Cincinnati, OH; S. R. FEDERMAN, Department of Physics & Astronomy, University of Toledo, Toledo, OH; AND P. C. STANCIL, Department of Physics & Astronomy and the Center for Simulation Physics, University of Georgia .
A. Dalgarno first suggested thirty-two years ago that doubly-ionized X2+ elements reacting with H2 could lead to the formation of molecules in regions with a significant X-ray flux. However, few investigations of the effects of X2+ on the formation of molecules have actually been conducted. Recent studies have found the reaction rate coefficients to be orders of magnitude higher than previously thought. This fact, combined with a renewed interest in the physics and chemistry of X-ray Dominated Regions (XDRs), points to a need to study the effects of X2+ on molecule formation. We investigated how S2+ + H2 affects the formation of SH+ for atomic gas exposed to an X-ray continuum typical of an Active Galactic Nucleus (AGN). As long as the fraction of S2+ + H2 reactions which lead to SH+ formation exceeds a few percent, this process will be the dominant formation pathway for SH+. This potentially has major consequences for our understanding of sulfur chemistry in galaxies where the energetics is dominated by AGN activity.