IR computed spectral lines vs. ACE-FTS Solar Atlas observations (black dottedline). The 26-level models 1401 (blue line) and 1401a (orange dashed line) follow the continuum, and 85-level models 1401b (purple dashed-dotted line) and 1401c (red dashed-double-dotted line) fit the observations. Term-term transitions: (a) 33 200.6 Å, (b) 36 807.6 Å, (c) 38 664.9, 38 669.1, and 38 670.4 Å, and (d) 71 092.0 and 71 097.4 Å. See Table 3 for line parameters. Although synthetic lines are deeper than observations, Mg I model 1401c with the new DW ϒ_ij data produces a better match throughout part of the IR range.