Maximum of the mass spectrum, m_peak, (solid isolines) and the typical fragment separation, d_peak, (dashed isolines) given by PAGI as a function of the shell surface density Σ and the external pressure . The thick lines show the maximum of the CMF, m_CMF, and typical separation of clumps, d_MST, obtained from our ¹³CO APEX observations. The thin dotted lines show the m_CMF – d_MST intersection at Σ = 9 × 10^-4 g cm^-2 and P_EXT = 1.4 × 10^-12 dyne cm^-2.