Photodissociation as a probe of the H3+ avoided crossing seam.

Abstract

Experiments are conducted to investigate the role of the avoided crossing seam in the photodissociation of H3+. Three-dimensional imaging of dissociation products is used to determine the kinetic energy release and branching ratio among the fragmentation channels. Vibrational distributions are measured by dissociative charge transfer of H2+ products. It is found that the photodissociation of hot H3+ in the near-ultraviolet produces cold H2+, but hot H2. Modelling the wavepacket dynamics along the repulsive potential energy surface accounts for the repopulation of the ground potential energy surface. The role of the avoided crossing seam is emphasized and its importance for the astrophysically relevant charge transfer reactions underlined. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.