Ion irradiation of crystalline H2O-ice: Effect on the 1.65-μm band

Rachel M.E. Mastrapa, Robert H. Brown

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64 Scopus citations


We have found that 0.8 MeV proton irradiation of crystalline H2O-ice results in temperature dependent amorphization. The H2O-ice's phase was determined using the near infrared spectrum from 1.0 μm (10,000 cm-1) to 2.5 μm (4000 cm-1). In crystalline H2O-ice, the 1.65-μm (6061 cm-1) band is strong while it is nearly absent in the amorphous spectrum [Schmitt, B., Quirico, E., Trotta, F., Grundy, W.M., 1998. In: Schmitt, B., de Bergh, C., Festou, M. (Eds.), Solar System Ices. Kluwer Academic, Norwell, MA, 1998, pp. 199-240]. In this experiment, at low temperatures (9, 25, and 40 K), irradiation of crystalline H2O-ice produced the amorphous H2O-ice's spectrum. However, at 50 K, some crystalline absorptions persisted after irradiation and at 70 and 100 K the crystalline spectrum showed only slight changes after irradiation. Our results agree with previous H2O-ice irradiation studies examining the crystalline peaks near 44 and 62 μm by Moore and Hudson [Moore, M.H., Hudson, R.L., 1992. Astrophys. J. 401, 353-360] and near 3.07 μm by Strazzulla et al. [Strazzulla, G., Baratta, G.A., Leto, G., Foti, G., 1992. Europhys. Lett. 18, 517-522] and by Leto and Baratta [Leto, G., Baratta, G.A., 2003. Astron. Astrophys. 397, 7-13]. We present a method of measuring band areas to quantify the phase and radiation dose of icy Solar System surfaces.

Original languageEnglish (US)
Pages (from-to)207-214
Number of pages8
Issue number1
StatePublished - Jul 2006


  • Ices
  • Infrared observations
  • Kuiper belt objects
  • Radiation chemistry
  • Spectroscopy

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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