Computed gas-phase abundances of HC₃N, C₆H, CH₃OH as a function of the local density of each SPH particle at the peak density of cloud A and B, i.e., at t = 35:82 Myr and t = 45:96 Myr, respectively. Points in blue are the results obtained for cloud A, while points in red show the results obtained in the case of cloud B. The black line presents the median density of both clouds and the filled area indicates the range on which the abundance dispersion of Fig. 11 was computed.