Model DR_P at t = 400 yr and an inclination angle i = 30°. Results are presented for four different values of the jet–ambient gas mixing degree j_mix (from top to bottom): 0.0, 0.3, 0.6, 1.0. Left: maps of H₂ column density obtained by integration over the velocity range between 1 and +150 km s⁻¹. Right: molecular mass–velocity relationship (black). The best-fitting power laws for the two velocity intervals: v ≤10 km s⁻¹ (left) and 10 < v ≲20 km s⁻¹ are drawn in dashed red. The index γ is shown inside the panel. The exponential best fit is drawn in blue and the exponent v₀ is given for each j_mix value.