Top: spectra for the atomic, molecular, and ionic gas tracers, H i (blue), ¹³CO (green), [C ii] (black), and [N ii] (red), averaged over all LOS within b = ±0.̊25 plotted as main beam temperature, T_mb, versus V_LSR. The ionized gas tracers are seen to extend to much higher velocities, corresponding to the innermost leading edge of the Scutum arm, than the molecular gas as traced by ¹³CO. Bottom: expanded view of the ionized gas emission after subtracting out the [C ii] and [N ii] emission arising from the molecular clouds traced by ¹³CO. The solid green curves represent two of the Gaussian components fit to the ¹³CO emission. The dashed green curve is the residual ¹³CO after subtraction. Gaussian profiles were used to fit the [C ii] and [N ii] emission associated with the gas at velocities <110 km s^-1, while keeping their V_LSR at the peak and FWHM the same as the ¹³CO, and only adjusting their peak intensities. Thus what remains for V_LSR ≥ 110 km s^-1 is the [C ii] and [N ii] excess arising solely from the highly ionized gas with no associated CO.