Oscillator strengths (10-70 eV) for absorption, ionization and dissociation in H2, HD and D2, obtained by an electron-ion coincidence method

The gross spectral behaviour of the dipole oscillator strengths for absorption, ionization and dissociation of H2, HD and D2 has been measured over the energy range of 0 to 70 eV, using the technique of detection of forward-scattered 8 keV electrons in delayed coincidence with the ions. A quantitative collection of ionic fragments is ensured up to kinetic energies of 20 eV. The absorption results are in excellent agreement with those of Samson and Cairns (1965). By subtracting the total ionization spectrum from absorption, a region about 1 eV wide is found above the ionization potential where part of the oscillator strength goes into neutral formation. No appreciable isotope effect is observed in this region.