The role of low-energy (≤ 20 eV) electrons in astrochemistry

SURFACE SCIENCE

卷:652

Article

Boyer, Michael C.¹  Rivas, Nathalie²  Tran, Audrey A.²  Verish, Clarissa A.²  Arumainayagam, Christopher R.² 

[1] Clark Univ, Dept Phys, Worcester, MA 01610 USA

[2] Wellesley Coll, Dept Chem, Wellesley, MA 02481 USA

关键词: Astrochemistry;    Low-energy electrons;    Temperature programmed desorption;    Infrared reflection absorption spectroscopy;    Cosmic ices;    Synthesis of prebiotic molecules;   

DOI  :  10.1016/j.susc.2016.03.012

来源: Elsevier

【 摘 要 】

UV photon-driven condensed phase cosmic ice reactions have been the main focus in understanding the extraterrestrial synthesis of complex organic molecules. Low-energy (<= 20 eV) electron-induced reactions, on the other hand, have been largely ignored. In this article, we review studies employing surface science techniques to study low-energy electron-induced condensed phase reactions relevant to astrochemistry. In particular, we show that low-energy electron irradiation of methanol ices leads to the synthesis of many of the same complex molecules formed through UV irradiation. Moreover, our results are qualitatively consistent with the hypothesis that high-energy condensed phase radiolysis is mediated by low-energy electron-induced reactions. In addition, due to the numbers of available low-energy secondary electrons resulting from the interaction of high-energy radiation with matter as well as differences between electron- and photon-induced processes, low-energy electron-induced reactions are perhaps as, or even more, effective than photon-induced reactions in initiating condensed-phase chemical reactions in the interstellar medium. Consequently, we illustrate a need for astrochemical models to include the details of electron-induced reactions in addition to those driven by UV photons. Finally, we show that low-energy electron-induced reactions may lead to the production of unique molecular species that could serve as tracer molecules for electron-induced condensed phase reactions in the interstellar medium. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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