Lyman-α excitation spectra in the photodissociation of the doubly excited states of H2

Doubly excited states of molecular hydrogen: theoretical absorption and photodissociation cross sections

“…Glass-Maujean measured the Lyman-α [3,4], Balmer-α and Balmer-β [4] and, with collaborators, the branching ratio of the H(3l) fragments of Balmer-α emission [5] for the photodissociation of H 2 in the energy region of the doubly excited states. Arai et al measured the Lyman-α emission [6] and the coincidence Lyman-α-Lyman-α [7] originated from photodissociation of doubly excited states.…”

Multiphoton dynamics of H2 with 248 nm picosecond and femtosecond pulses

“…This is similar for transitions to a 1 ⌸ u ϩ or 1 ⌸ u Ϫ state, but it is noted that these different parity states show different behavior in dissociation and ionization dynamics. 26 The equivalent threephoton final state at 14.96 eV of H 2 can be compared with the XUV one-photon studies by Arai et al 33 and Glass-Maujean et al 34 The high-resolution absorption spectra of Glass-Maujean et al 34 show different rotational transitions to the D 1 ⌸ u (vϭ4) and the BЉ 1 ⌺ u ϩ (vϭ2) state in the 14.96 eV region. Also, these two states are seen in the Lymann-␣ fluorescence excitation spectrum, which shows that they also predissociate to the nearby H(nϭ1)ϩH(nϭ2) dissociation limit.…”

“…The major interaction is the coupling of the BЈ 1 ⌺ u ϩ vibrational continuum with the BЉ 1 ⌺ u ϩ and D 1 ⌸ u ϩ Rydberg states. According to the XUV one-photon spectra of Glass-Maujean et al 34 and Arai et al 33 transitions to two states, the BЉ 1 ⌺ u ϩ (vϭ2) and the D 1 ⌸ u ϩ (vϭ4), lie in the energy region of the three photon level. These states predissociate to the second ͓H(nϭ1)ϩH(nϭ2)͔ dissociation limit, so this is consistent with the main observation of a three-photon dissociation towards this limit.…”

Formation of metastable atomic hydrogen in the 2sstate from symmetry-resolved doubly excited states of molecular hydrogen

“…Thus, a consensus that the precursor state of the fast H(2s) fragment is the Q 2 1 u (1) state has been developed. Because the state was also known as the main contributor to the cross section for the H(2p) atom formation [16][17][18][19], the Q 2 1 u (1) state has been considered to dissociate into H(2s) + H(2p). However, this conclusion needs to be re-examined since (i) the theoretical potential energies and resonance widths of the doubly excited states of H 2 by the recent calculation with large configuration bases [6] differ from those by the former calculation [15] and (ii) the velocity distributions of H(2s) fragments depend on the electron impact energy [20], showing a possibility of contributions from the neutral and ionic molecular states other than the Q 2 1 u (1) state in the electron collision experiment by Misakian and Zorn.…”