Results of slab models. a) Integrated intensity of the R(6) 10⁰0–00⁰0 line depending on the density for different kinetic temperatures and column densities. Solid lines show models that only consider collisions, while dashed and dotted lines represent models with a pumping radiation field of a 750 K blackbody diluted by W = 0.1 (dashed line) or W = 0.01 (dotted line). Red, blue, and green lines show results for column densities of 10¹³ cm^-2, 10¹⁵ cm^-2, and 10¹⁷ cm^-2, respectively. b) Total integrated intensity of all HCN lines between 13.7 and 14.1 μm for the same parameters as panel a). c) Ratio of panels a) and b) compared to the observed ratio toward AS 205 (N).