In order to understand much of the chemistry that underpins astronomical phenomena (e.g. star and planet formation) it is essential to probe the physico-chemistry of ice surfaces under astronomical conditions. The physical properties and chemical reactivity of such icy surfaces depends upon its morphology. Thus it is necessary to explore how the morphology of astrochemical ices is influenced by their local environment (e.g. temperature and pressure) and the mechanisms by which they are processed. In this paper we report the results of a series of experiments to explore the morphology of a variety of molecular ices using VUV spectroscopy. Spectral signatures are found that may allow the morphology of such ices to be identified.

RAIRS experiments have been performed to investigate the adsorption of NO on Pt{211}. Results show that adsorption is complex and strongly temperature dependent. At 307 K, three bands are seen at saturation with frequencies of 1801, 1609, and 1576 cm-1. However, at 120 K only two bands, at 1688 and 1620 cm-1, are observed. To help with the assignment of these vibrational bands, DFT calculations were also performed. The calculations show that a bridged NO species, bonded to the step edge, is the most stable species on the surface and gives rise to the band observed at 1610−1620 cm-1. The calculations also suggest that the temperature dependence of NO adsorption on Pt{211} can be assigned to NO dissociation which occurs at room temperature but not at 120 K. In particular, the RAIRS band observed at 1801 cm-1, which is observed on adsorption at 307 K but not at 120 K, is tentatively assigned to the formation of an O−NO complex. This species forms when a NO molecule bonds on top of an O atom, which results from the dissociation of NO on the Pt{211} surface at room temperature.

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The authors present the results of a morphological study of solid ammonia using both Fourier-transform infrared and vacuum ultraviolet (VUV) spectroscopy. Dramatic changes in the VUV and infrared spectra at temperatures between 65 and 85 K provide a deeper insight into the structure of ammonia ice particularly with the observation of an exciton transition at 194 nm (6.39 eV) in the VUV spectrum, revealing a structure that is composed of crystallites. A complementary structure is observed in the IR spectrum at 1100 cm(-1) which is assigned to the symmetric deformation of ammonia molecules at the surfaces of the crystallites. Such spectral signatures may be used to identify the environment within which the ammonia ice is formed and provide a new route for obtaining information on the physical and chemical conditions occurring within the interstellar medium, on the surfaces of planetary bodies, and in Kuiper belt objects.

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Synchrotron radiation is a good mimic of solar radiation and therefore has been widely used to study photo-induced physics and chemistry in the terrestrial atmosphere. In this paper we review how synchrotron radiation is being used as a tool for investigating atmospheric physics and chemistry with particular emphasis on studies related to ozone depletion, global warming and ionospheric phenomena. The paper concludes with a discussion of the new possibilities that the next generation of synchrotron-based light sources will provide.

In this paper we report the results of the first experimental study of the irradiation of low temperature water ice (30 and 90 K) using low energy (4 keV) 13C+ and 13C2+ ions. 13CO(2) and H2O(2) were readily formed within the H2O ice with the product yield and growth rate observed to be highly dependent on both the sample temperature and ion charge state.

Graphite intercalation compounds (GICs) of the type KC x (CH 3 NH 2 ) y have been prepared by in situ amination of stage-II C 24 K and stage-IV C 48 K, and studied by time-of-flight neutron diffraction. As the vapor pressure of methylamine is increased the compounds pass through a rich sequence of staging transitions, in which the regular repeat of n empty graphite layers is progressively filled by intercalant. In these staging transitions, n always changes by -1. We therefore observe lower stage unaminated compounds as methylamine is introduced into the starting compounds. Isotopic substitution of CD 3 ND 2 for CD 3 NH 2 has enabled us to determine the detailed structure of the fully aminated stage-I and stage-II end compounds, C 24 K(CH 3 NH 2 ) 3 and C 48 K(CH 3 -NH 2 ) 3 . We find that the interlayer structure is based on 3-fold coordinated potassium ions and is relatively insensitive to the stage.