H. Rottke et al., 2-PHOTON DISSOCIATIVE PHOTOIONIZATION AND PHOTODISSOCIATION OF SINGLEH2B (1)SIGMA(+)(U)(NU=5) ROTATIONAL STATES, Journal of physics. B, Atomic molecular and optical physics, 30(18), 1997, pp. 4049-4064
We report on an experimental study of dissociative photoionization and
neutral dissociation of H-2 by two-photon excitation from single B (1
) Sigma(u)(+)(v = 5) rotational states (photon energy approximate to 4
eV). The B-state rovibrational levels are excited in the same light p
ulse by three-photon absorption from X (1) Sigma(g)(+)(v = 0). Angle r
esolved photoelectron and ion kinetic energy distributions allow us to
discriminate between the different decay channels. Neutral decay is d
etected by one-photon ionization of excited atomic hydrogen product st
ates. The kinetic energy distribution of photoelectrons from dissociat
ive photoionization shows an oscillatory structure which depends on th
e initial B-state rotational quantum number J. An indication of a corr
esponding structure in the ion kinetic energy distributions is only fo
und for J = 0. similar to results reported by Verschuur et al we find
neutral decay preferentially into high principal quantum number atomic
states. The results indicate that the H-2 Q(1) doubly excited states
play a crucial role in the decay processes.