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Abstract

The H-3(+) ion is the simplest polyatomic molecule. Apart from its
fundamental role as a benchmark system for theoretical calculations, it
has attracted a lot of attention as one of the main drivers of an active
interstellar ion-neutral chemistry network. H-3(+) spectroscopy has
contributed greatly to astrochemistry, and experiment and theory have
both developed tremendously throughout the years, following the
ground-breaking work by Oka. To date, the highest-lying identified
H-3(+) transitions were obtained using an action spectroscopy technique,
employing stored H-3(+) ions in a cryogenic ion trap. This approach was
pioneered by Schlemmer and Gerlich for N-2(+) , and is widely used today
- in one form or another - for spectroscopic studies of interstellar
ions. In this work, we explore the possibility to extend the range for
H-3(+) action spectroscopy even further, into the regime above 20000
cm(-1), in order to bridge the gap to the rich pre-dissociation spectrum
of states near the dissociation limit that was obtained by Carrington et
al. and remains unassigned after more than 30 years. (C) 2021 The
Authors. Published by Elsevier Inc.