Photoionization of hydrogen and deuterium

Abstract

Cross sections for the formation of slow molecular and energetic fragment ions in the photoionization of hydrogen and deuterium have been determined using synchrotron radiation within the energy range 25–40 eV. Superexcited states have been shown to play an important role in the photoionization process but recently predicted resonance effects have not been observed.

Production of excited atomic hydrogen and deuterium from H2and D2photodissociation

“…doubly excited states and the H + 2 ionization thresholds included in the theoretical calculations; (a) doubly excited states; (b) ionization thresholds. For each Q state, only the dominant doubly excited confi guration is indicated (see[25] for details).…”

Tilted Liquid Crystal Alignment on Asymmetrically Grooved Porous Alumina Film

“…Considering the accuracy of the pressure measurement (SEM ∼ 0.02 Torr), this is the first clear observation indicating the differing phase matching effects between the two isotopes. Furthermore, this observation also indicates the other factor of different photoabsorption cross sections indirectly via the Kramers-Kronig relation and, in fact, the photoabsorption cross section of H 2 molecules is significantly larger than that of D 2 molecules in this spectral region [20] 3 . Since the larger photoabsorption cross section of H 2 molecules by itself can explain the observed smaller harmonic signals from them qualitatively, one should be careful to evaluate the net magnitude of the enhancement.…”

“…In measuring the intensities, however, they ignored the differences in phase-matching effects of harmonics during their propagation, which can give measurable contributions to the observed harmonics [20]- [24]. Since it is a hard task to control the conditions of jetted gases and determine the phase-matching effects, it is experimentally important to investigate the phenomenon by using a gas cell, with which the conditions of gases can be controlled precisely.…”

Production of excited atomic hydrogen and deuterium from H2 and D2 photodissociation

“…Barat-Lichten rules [29] that correlate the separate-atom limit to the H 2 doubly excited states and the H + 2 ionization thresholds included in the theoretical calculations; (a) doubly excited states; (b) ionization thresholds. For each Q state, only the dominant doubly excited confi guration is indicated (see [25] for details).…”

“…The continuum states are evaluated by means of the L 2 close-coupling method [24] by using the same H + 2 orbitals and B-spline functions as for bound states. The "discretized" continuum states lead to total photoionization cross sections that are practically identical to the experimental ones [25]. Vibrational (bound and dissociative) wavefunctions have also been expanded in a basis of B-splines.…”