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Title: Photochemistry of Coronene in Cosmic Water Ice Analogs at Different Concentrations

Abstract

This work presents the photochemistry of ultraviolet (UV) irradiated coronene in water ices at 15 K studied using mid-infrared Fourier transform (FTIR) spectroscopy for C{sub 24}H{sub 12}:H{sub 2}O at concentrations of (1:50), (1:150), (1:200), (1:300), and (1:400). Previous UV irradiation studies of anthracene:H{sub 2}O, pyrene:H{sub 2}O, and benzo[ghi]perylene:H{sub 2}O ices at 15 K have shown that aromatic alcohols and ketones, as well as CO{sub 2} and H{sub 2}CO, are formed at very low temperatures. Likewise, here, in addition to the coronene cation, hydroxy-, keto-, and protonated coronene (coronene H{sup +}) are formed. The rate constants for the decay of neutral coronene and for the formation of photoproducts have been derived. It is shown that Polycyclic Aromatic Hydrocarbons (PAHs) and their UV induced PAH:H{sub 2}O photoproducts have mid-infrared spectroscopic signatures in the 5–8 μ m region that can contribute to the interstellar ice components described by Boogert et al. as C1–C5. Our results suggest that oxygenated and hydrogenated PAHs could be in UV-irradiated regions of the interstellar medium where water-rich ices are important.

Authors:
 [1]; ; ; ;  [2]
  1. Departamento de Física, Centro Federal de Educação Tecnológica Celso Suckow da Fonseca, Av. Maracanã 229, 20271-110 Rio de Janeiro, RJ (Brazil)
  2. NASA Ames Research Center, Mail Stop 245-6, Moffett Field, CA 94035-1000 (United States)
Publication Date:
OSTI Identifier:
22679745
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 848; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; ANTHRACENE; CARBON DIOXIDE; DECAY; FOURIER TRANSFORMATION; HYDROGENATION; ICE; INFRARED SPECTRA; IRRADIATION; MOLECULES; PERYLENE; PHOTOCHEMISTRY; POLYCYCLIC AROMATIC HYDROCARBONS; PROTOPLANETS; PYRENE; SIMULATION; SPACE; ULTRAVIOLET RADIATION; WATER

Citation Formats

De Barros, A. L. F., Mattioda, A. L., Ricca, A., Cruz-Diaz, G.A., and Allamandola, L. J.. Photochemistry of Coronene in Cosmic Water Ice Analogs at Different Concentrations. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8C71.
De Barros, A. L. F., Mattioda, A. L., Ricca, A., Cruz-Diaz, G.A., & Allamandola, L. J.. Photochemistry of Coronene in Cosmic Water Ice Analogs at Different Concentrations. United States. doi:10.3847/1538-4357/AA8C71.
De Barros, A. L. F., Mattioda, A. L., Ricca, A., Cruz-Diaz, G.A., and Allamandola, L. J.. Fri . "Photochemistry of Coronene in Cosmic Water Ice Analogs at Different Concentrations". United States. doi:10.3847/1538-4357/AA8C71.
@article{osti_22679745,
title = {Photochemistry of Coronene in Cosmic Water Ice Analogs at Different Concentrations},
author = {De Barros, A. L. F. and Mattioda, A. L. and Ricca, A. and Cruz-Diaz, G.A. and Allamandola, L. J.},
abstractNote = {This work presents the photochemistry of ultraviolet (UV) irradiated coronene in water ices at 15 K studied using mid-infrared Fourier transform (FTIR) spectroscopy for C{sub 24}H{sub 12}:H{sub 2}O at concentrations of (1:50), (1:150), (1:200), (1:300), and (1:400). Previous UV irradiation studies of anthracene:H{sub 2}O, pyrene:H{sub 2}O, and benzo[ghi]perylene:H{sub 2}O ices at 15 K have shown that aromatic alcohols and ketones, as well as CO{sub 2} and H{sub 2}CO, are formed at very low temperatures. Likewise, here, in addition to the coronene cation, hydroxy-, keto-, and protonated coronene (coronene H{sup +}) are formed. The rate constants for the decay of neutral coronene and for the formation of photoproducts have been derived. It is shown that Polycyclic Aromatic Hydrocarbons (PAHs) and their UV induced PAH:H{sub 2}O photoproducts have mid-infrared spectroscopic signatures in the 5–8 μ m region that can contribute to the interstellar ice components described by Boogert et al. as C1–C5. Our results suggest that oxygenated and hydrogenated PAHs could be in UV-irradiated regions of the interstellar medium where water-rich ices are important.},
doi = {10.3847/1538-4357/AA8C71},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 848,
place = {United States},
year = {2017},
month = {10}
}