X-shooter spectrum between 3300 and 4200 Å illustrating the presence of H₂ absorption. The uppermost, blue-framed panel shows an overview, while the lower 5 panels show zoom-ins of 100 Å each below 3800 Å, where most of the Lyman-Werner absorption bands are located. Light-grey lines are the normalized spectrum, while dark-grey lines indicate the error spectrum. The solid red line denote the synthetic H₂ model, with individual transitions up to J = 5 transitions marked with red labels. The dashed lines show synthetic H₂ models corresponding to the 1σ errors on the measured molecular content. In the top panel, we also mark prominent metal absorption lines previously detected in GRB-DLAs (Christensen et al. 2011) and those of the intervening systems. In the lower panels, J0,J1, and so forth denote transitions from the J = 0, J = 1 rotational level of the vibrational ground state of the Lyman-Werner bands of H₂.