Production of excited atomic hydrogen and deuterium from H 2 and D 2 photodissociation

We have measured the production of Lyman α and Balmer α fluorescence from atomic H and D for the photodissociation of H2, HD and D2 by linearly-polarized photons with energies between 22 and 64 eV. We discuss systematic uncertainties associated with our data, and compare our results with previous experimental results and ab initio calculations of the dissociation process. We comment on the discrepancies. (Some figures in this article are in colour only in the electronic version)