We have investigated the elementary processes occurring in H-2 + H-2 collisions by integrating large batches of quasiclassical trajectories. This has allowed us to calculate the vibrational state-selected rate coefficients as well as their aggregations in classes leading to the same products and their dependence on temperature. The contribution of the Various elementary and aggregated processes both to the allocation of energy among the various vibrational states of the products and to the production of hydrogen atoms is analyzed. Some correlations of these contributions with the value of the impact parameter and with some characteristics of the reactive mechanism are also discussed; The key importance of hydrogen exchange processes is also singled out.