Top left: self-shielding functions for (solid lines) and ¹⁴N₂ (dotted lines) at various temperatures defining their excitation state and thermal Doppler broadening. Top right: shielding of ¹⁴N 15N photodissociation by ¹⁴N₂ at various excitation and Doppler broadening temperatures. Bottom: shielding of (solid lines) and ¹⁴N₂ (dotted lines) photodissociation by H and H₂ as a function of their column densities.