Concentration of important absorbing molecules and neutral atoms as a function of optical depth and temperature at [M/H] = +2.0 (top), [M/H] = 0.0 (middle), and [M/H] = −2.0 (bottom). These species deplete at the given pressure range for the irradiated hot Jupiter WASP-19b (see main text). The grey shaded region (left panels) corresponds to the structure inversion and shows the window of the observable atmosphere from which most of the spectrum emerges (in the CO, H₂O, and TiO molecular bands pseudo-continuum). We notice that in the upper atmosphere (τ < 10⁻²), H₂O, TiO, and VO dissociate whereas neutral atomic oxygen remains constant. We find that CO remains constant throughout the atmosphere of WASP-19b. The temperature inversion (right panels) causes the wiggles along the structure, causing CO bands to emerge in emission.