Detalles de publicación
INFRARED SPECTROSCOPY OF HYDROGENATED FULLERENES (FULLERANES) AT EXTREME TEMPERATURES
1Instituto de Astrofísica de Canarias, Vía Lactea s/n, E-38200, La Laguna, Tenerife, Spain, 2 Departamento de Astrofísica. Universidad de La Laguna. E-38200, La Laguna, Tenerife, Spain 3Istituto Nazionale di Astrofisica – Osservatorio Astrofisica di Catania, Via S. Sofia 78, 95123, Italy 4Actinium Chemical Research, Via Casilina 1626/A, 00133 Rome, Italy 5CSIC, Consejo Superior de Investigaciones Cientificas, Madrid, Spain
The infrared spectra, as well as the integrated molar absorptivity (Ψ) and the molar extinction coefficient (ε) of each infrared transition of the hydrogenated fullerenes (known as fulleranes) C60H36, C60H18, and C70H38, and a mixture of fulleranes generally referred as 77% of C60Hx and 22% C70Hy with x≈y > 30, are presented and discussed. These data are useful for the search, identification, and quantitative determination of fulleranes in space after the recent discovery that their parent molecules, C60 and C70, are more abundant in space than initially thought, being present in a variety of H-rich circumstellar environments such as planetary nebulae and only mild H-deficient R Coronae Borealis stars, and in the interstellar medium. It is shown that the C-H stretching band of the fulleranes C60H36, C60H18, and C70H38, and their mixture may be the most useful for the identification of these molecules because their Ψ and ε values are unique in terms of strength overcoming by far the typical Ψ and ε values of reference molecules such as adamantane and docosane, as well as typical ε literature data for aliphatic molecules. In contrast with the rather simple infrared spectra of C60H36 and C60H38, the infrared spectra of two C60H18 isomers are reported as characterized by a rich number of bands which may allow an easier identification than the higher homologues. The dependence of the infrared bands of fulleranes on temperature was studied over a wide range of temperatures (from -180°C to +250°C) and extrapolated to 0 K.