Normalized intensities Ĩ_ij of CH⁺ of v = 0 → 0, J → J–1 (green), v =1 → 0, J → J + 1 (blue), and v = 2 → 1, J → J + 1 (red) following chemical-pumping while considering the observed population densities of H₂ and temperature in the Bar and d203-506. Emissions from v = 1 and v = 2 levels are observed with NIRSpec. Emission from v = 0 levels are observed with Herschel/PACS and Herschel/HIFI, and we considered that the emission comes from a 2′′ wide filament (Joblin et al. 2018).