SPECTROSCOPY OF H-3(+) - PLANETS, CHAOS AND THE UNIVERSE

This review discusses the H-3(+) molecular ion and its deuterated isotopomers. The ion is important because of its fundamental nature, astrophysical significance and dynamical richness. The following topics are discussed: the discovery of H-3(+), its unusual bonding and the important role played by ab initio electronic-structure calculations; the formation of H-3(+) and its importance in models of the interstellar medium; the unusual spectroscopy of H-+(3) and the accurate quantum calculations which led to laboratory observations; the failure to detect H-3(+) in the interstellar medium and its accidental observation in Jupiter; work on H-+(3) in the giant planets and other astronomical emission spectra; the very unusual infrared photodissociation spectrum of H-3(+); and the classical and quantal behaviour of the molecule at its dissociation limit.