Has it been observed that the dihydrogen molecule dissociates into ions?
Surely1. At the end of the day, it is just the matter of supplying enough energy: the homolysis requires approximately 4.5 eV per hydrogen molecule, while for heterolysis more than 17 eV per molecule must be provided.



1) G. Busca, A. Vaccari, Heterolytic dissociation of hydrogen on high-temperature methanol synthesis catalysts, Journal of Catalysis, 108(2), 1987, 491-494, http://dx.doi.org/10.1016/0021-9517(87)90198-9.