THz Time-Domain Spectroscopy of Mixed CO2-CH3OH Interstellar Ice Analogs

Abstract

The icy mantles of interstellar dust grains are the birthplaces of the primordial prebiotic molecular inventory that may eventually seed nascent solar systems and the planets and planetesimals that form therein. Here, we present a study of two of the most abundant species in these ices after water: carbon dioxide (CO2) and methanol (CH3OH) using TeraHertz (THz) time-domain spectroscopy and mid-infrared spectroscopy. We study pure and mixed-ices of these species, and demonstrate the power of the THz region of the spectrum to elucidate the long-range structure (i.e. crystalline versus amorphous) of the ice, the degree of segregation of these species within the ice, and the thermal history of the species within the ice. Finally, we comment on the utility of the THz transitions arising from these ices for use in astronomical observations of interstellar ices.

arXiv commentAccepted for publication in Physical Chemistry Chemical Physics

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Cited by in corpus (7)

• Broadband spectroscopy of astrophysical ice analogs. I. Direct measurement of complex refractive index of CO ice using terahertz time-domain spectroscopy
• Vacuum ultraviolet photoabsorption spectroscopy of space-related ices: Formation and destruction of solid carbonic acid upon 1~keV electron irradiation
• Mid-IR and VUV Spectroscopic Characterisation of Thermally Processed and Electron Irradiated CO2 Astrophysical Ice Analogues
• Comparative Electron Irradiations of Amorphous and Crystalline Astrophysical Ice Analogues
• Infrared free-electron laser irradiation of carbon dioxide ice
• The Role of Terahertz and Far-IR Spectroscopy in Understanding the Formation and Evolution of Interstellar Prebiotic Molecules
• Broadband spectroscopy of astrophysical ice analogues: II. Optical constants of CO and CO${}_2$ ices in the terahertz and infrared ranges