High-Order Harmonics Fourier Transform Spectroscopy of Two-Photon Dissociative Ionization of Hydrogen Molecules

High-order harmonic generation provides us a coherent femtosecond pulse in a vacuum ultraviolet wavelength region. We have investigated the two-photon dissociative ionization of deuterium molecules by Fourier transform spectroscopy with a high-order harmonic generation pulse. We measured the delay-dependent kinetic energy distribution of the deuteron fragments resulting from the dissociative ionization by scanning the delay between the two replicas of the high-order harmonic generation pulse. From the Fourier transform analysis, we successfully distinguished the harmonic order, which induced the photodissociation and provided the specific kinetic energy to the fragments via the repulsive electronic excited state.