Isoprene and its oligomers, terpenes, are expected to be present, along with other complex organic molecules, in the diverse environments of the ISM and in our solar system.
Due to insufficient spectral information of these molecules at low temperature, the detection and understanding of the importance of these molecules has been rather incomplete.
For this purpose, we have carried out the vacuum ultraviolet (VUV) photoabsorption measurements on pure molecular ices of isoprene and a few simple terpenes: limonene, α-pinene and β-pinene by forming icy mantles on cold dust analogs. From these experiments, we report the first low-temperature (10 K) VUV spectra of isoprene and its oligomers, limonene, α-pinene, and β-pinene.
VUV photoabsorption spectra of all the molecules reported here reveal similarities in the ice and gas phase, as expected, except for isoprene, where a prominent red shift is observed in the ice phase absorption. This unique property of isoprene, along with distinctive absorption at longer wavelengths, supports its candidature for detection on icy bodies.
R Ramachandran, S Pavithraa, J K Meka, K K Rahul, J -I Lo, S -L Chou, B -M Cheng, B N Rajasekhar, Anil Bhardwaj, N J Mason, B Sivaraman
Comments: 4 pages, 4 figures
Subjects: Astrophysics of Galaxies (astro-ph.GA); Atmospheric and Oceanic Physics (physics.ao-ph); Chemical Physics (physics.chem-ph)
Cite as: arXiv:2509.20966 [astro-ph.GA] (or arXiv:2509.20966v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2509.20966
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Journal reference: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 268 (2022), 120586
Related DOI:
https://doi.org/10.1016/j.saa.2021.120586
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Submission history
From: Ragav Ramachandran
[v1] Thu, 25 Sep 2025 10:09:35 UTC (238 KB)
https://arxiv.org/abs/2509.20966
Astrochemistry, Astrobiology,