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Infrared spectra of (CH3)2O and (CH3)2O + H2O at low temperature |
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| Authors: | L Schriver-Mazzuoli J M Coanga A Schriver P Ehrenfreund |
| Institution: | a Laboratoire de Physique Moléculaire et Applications, Unité Propre du CNRS, Université Pierre et Marie Curie, Tour 13, Case 76, 4 Place Jussieu, 75252, Paris Cedex 05, France b Laboratoire d’Etude des Nuisances Atmosphériques et de Leurs Effets, Université Paris Nord, IUP Ville et Santé, Rue de la Convention, Bobigny 93017, France c Leiden Observatory, P.O. Box 9513, 2300, Leiden, RA, The Netherlands |
| Abstract: | Fourier transform infrared reflection spectroscopy (incidence angle of 5°) was used to characterize thin films of dimethyl ether (DME) and of mixtures containing water and DME between 10 and 160 K under a pressure of 10−7 mbar. Solid DME has two solid phases: an amorphous phase which is obtained below 65 K and a crystalline phase >65 K. From 90 K, DME begins to sublimate with surface binding energy of 20±2 kJ mol−1. Vibrational spectrum of DME trapped in water ice remains nearly unchanged from 30 to 120 K. Between 120 and 130 K, a large part of DME is released and strong changes in the frequencies and the profile of the absorptions of DME are observed. This behavior suggests the formation of clathrate hydrate. Below 120 K, the trapped DME is hydrogen-bonded to water molecules. |
| Keywords: | Infrared spectroscopy Interstellar molecules Ices Laboratory studies |
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