Astron. Astrophys. 333, 1025-1033 (1998)

Profile of CH₄ IR bands in ice mixtures

G. Mulas ^{1, 2}, G.A. Baratta ³, M.E. Palumbo ³ and G. Strazzulla <sup>3

1</sup> Dipartimento di Scienze Fisiche dell'Università di Cagliari, Via Ospedale 72, I-09124 Cagliari, Italy
² Osservatorio Astronomico di Cagliari, Str. 54, Loc. Poggio dei Pini, I-09012 Capoterra (CA), Italy
³ Osservatorio Astrofisico di Catania, V.le A. Doria 6, I-95125, Catania, Italy

Received 11 November 1997 / Accepted 28 January 1998

Abstract

We studied the infrared spectral characteristics of frozen methane (CH₄) in several astrophysically relevant ice mixtures, as deposited and after ion irradiation. We examined the profile (shape, width and peak position) of the CH₄ bands as a function of initial mixture, irradiation dose and warming up temperature, and compared our results with previously published laboratory and observational data. Finally, we present a list of spectra that may be used for direct comparison with present and future observations.

Key words: molecular data molecular processes dust, extinction ISM: molecules infrared: ISM: lines and bands methods: laboratory

Send offprint requests to: G. Strazzulla

Contents

• 1. Introduction
• 2. Experimental setup
• 3. Results
  • 3.1. The 1302 cm^-1 C-H deformation mode
  • 3.2. The 3010 cm^-1 C-H stretching mode
  • 3.3. Warm-up effects
• 4. Final remarks
• References

© European Southern Observatory (ESO) 1998

Online publication: April 28, 1998

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