Left: evaporation timescales of a few PAH clusters as a function of the intensity of the UV radiation field, obtained with a model considering the growth of clusters by collisions with a sticking coefficient S = 1, a hydrogen nuclei density of n_H = 1.5 × 10³ cm^-3, and a gas temperature of T = 100 K. The thin black lines show the slopes of –1, characteristic of single-photon evaporation, and of –6, indicative of highly multi-photon evaporations. Right: results of the model for a UV radiation field of G₀ = 4 × 10⁴ in units of Habing as a function of time for circumcoronene clusters when considering the growth of clusters by collisions with S = 1 (black dashed lines) or S = 0.01 (blue solid lines).