Proton production probability in the dissociative photoionization of H2

We report the proton production probability in the dissociative photoionization of H2 from its threshold to 36 eV. The method depends on differentiating the observed ratios of H+/H+2 with respect to the incident photon energy. The probability presented shows at least three states are involved in this energy region and is attributed to protons formed through the ground state 2Σ+g(1sσg) of H+2, the two-electron excited state 1Σ+u(2pσu2sσg) of H2, and the first excited state 2Σ+u(2pσu) of H+2 by comparing the present results with other observations and theoretical calculations. Further the results indicate that interference between the direct (2Σ+g) and resonant (1Σ+u) processes produces an appreciable amount of protons at photon energies of 20–25 eV.