Three velocity regimes with two inner constant profiles and an outer free-fall profile. The inner and outer constant velocity profiles have a velocity of 5.3 and 2.7 km s^-1, respectively, and the free-fall profile uses f = 0.3, M₀ = 1 M_⊙ and a = 1. Observed Herschel-HIFI spectra in black compared to the best-fitting model line profiles in red. The ratio of the modeled and observed continuum at the frequency of each line is given in respective legend. The vertical black dotted line marks the systemic velocity of G34. , over ΔV_LSR = 54–68 km s^-1.