Infrared Spectra and Radiation Stability of H 2 O 2 Ices Relevant to Europa

Abstract

In this paper we present spectra of H₂O₂-containing ices in the near- and mid-infrared (IR) regions. Spectral changes on warming are shown, as is a comparison of near-IR bands of H₂O and H₂O₂-containing ices. An estimate of the A-value (absolute intensity) for the largest near- IR feature of H₂O₂ is given. Radiation-decay half-lives are reported for 19 K and 80 K, and are related to the surface radiation doses on Europa. The radiation data show that H₂O₂ destruction is slower at 80 K than 19 K, and are consistent with the claim that icy material in the outermost micrometer of Europa's surface has been heavily processed by radiation.