Astrochemical laboratory experiments as analogs to Plutonian chemistry: Using FTIR spectroscopy to monitor the sublimation of irradiated 1:1:100 CO+H2O+N2 and 1:1:100 CH4+H2O+N2 ices

Stelmach, Kamil Bartłomiej

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https://hdl.handle.net/2142/96833 Copy

Description

Title

Astrochemical laboratory experiments as analogs to Plutonian chemistry: Using FTIR spectroscopy to monitor the sublimation of irradiated 1:1:100 CO+H2O+N2 and 1:1:100 CH4+H2O+N2 ices

Author(s)

Stelmach, Kamil Bartłomiej

Contributor(s)

• Cooper, Paul
• Yarnall, Yukiko

Issue Date

2017-06-21

Keyword(s)

Astronomy

Abstract

Pluto is a large icy body composed of N$_{2}$, CH$_{4}$, and H$_{2}$O ices. In many ways, Pluto can be seen as one large matrix isolation experiment where N$_{2}$ is the inert matrix that can act to trap and isolate reactive species. The temperature changes on the dwarf planet induce sublimation of N$_{2}$ from the surface. Any previously trapped reactive species could then react with the new ice or neighboring molecules. To see if this process might lead to a significant formation of molecules, Fourier-Transform Infrared (FTIR) Spectroscopy (4 cm$^{-1}$ resolution) was used to study and monitor the sublimation of ices created from irradiated gas mixtures of 1:1:100 CO+H$_{2}$O+N$_{2}$ or 1:1:100 CH$_{4}$+H$_{2}$O+N$_{2}$. The gas mixtures were initially prepared and deposited on a cold finger at a temperature of 6 K and a baseline vacuum of about 1 x 10$^{-7}$ Torr. Gas mixtures were irradiated using an electric discharge or a microwave discharge before deposition to create the unstable chemical species. To sublimate the matrix, the temperature was brought up step-wise in 5-10 K intervals to 45 K. Slow sublimation (10 min per step) resulted in the new species being trapped in a water ice. In addition to (FTIR) spectroscopy, chemical species were also identified or monitored using ultraviolet-visible (UV-Vis) spectroscopy and a residual gas analyzer (RGA). Carbon suboxide (C$_{3}$O$_{2}$), a common component found in meteorites and a potentially important prebiotic molecule, was formed only after the sublimation step. Other products formed included deprotonated versions of products formed in the original matrix ice. C$_{3}$O$_{2}$’s potential importance in Pluto’s surface chemistry and its overall astrobiological significance will be discussed.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/96833

DOI

https://doi.org/10.15278/isms.2017.WA09

Copyright and License Information

Copyright 2017 Kamil Bartłomiej Stelmach

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