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Experimental investigation on the photolysis of astrophysical ices containing acetic acid and its isomers (methyl formate and glycolaldehyde)

Grant number: 14/08643-0
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): July 01, 2014
Effective date (End): June 30, 2015
Field of knowledge:Physical Sciences and Mathematics - Astronomy
Principal researcher:Sergio Pilling Guapyassu de Oliveira
Grantee:Karla Faquine Rodrigues
Home Institution: Instituto de Pesquisa e Desenvolvimento (IP&D). Universidade do Vale do Paraíba (UNIVAP). São José dos Campos , SP, Brazil
Associated research grant:09/18304-0 - Synthesis and degradation of prebiotic molecular species at planetary atmospheres, comets and interstellar ice analogs, AP.JP


Acetic acid and its isomers (methyl formate and glycolaldehyde have been detected in different space environments, for example, in molecular clouds associated with star-forming region. Their abundances relative to molecular hydrogen in different regions vary greatly among themselves, which would be related to different mechanisms of formation and destruction. In space, these chemical species both in gaseous form and in the form of ices are constantly being subjected to intense ionizing radiation fileds (UV photons, X-rays, electrons and fast ions) that promote mechanisms of molecular dissociation. In this work we will perform an experimental study of astrophysical ice simulated in the laboratory, to understand which of the isomers that have the molecular formula C2H4O2 (acetic acid - CH3COOH, methyl formate - HCOOCH3 and glycolaldehyde - HOCH2CHO), would be the most destroyed in the presence of ionizing photons. in this first investigation we will analyse the data obtained recently on the photodissociation of acetic acid at the temperature of 12 K irradiated by photons in the ultraviolet and X-rays ( 6 eV to 1200 eV) . The experiments were performed inside a chamber ultra-high vacuum of the Laboratory for Astrochemistry and Astrobiology Univap (LASA) coupled SGM beamline at the National Synchrotron Light Laboratory (LNLS), Campinas, SP. During the irradiation, the frozen sample was monitored by Fourrier Transforemd infrared spectroscopy (FTIR). The data analysis will allow the determination of molecular cross-sections (destruction and the formation of children species). The results of this study will be compared with observational data and will help to elucidate the chemistry and physical chemistry existing between the isomers of acetic acid in regions of star formation.

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
RACHID, MARINA G.; FAQUINE, KARLA; PILLING, S. Destruction of C2H4O2 isomers in ice-phase by X-rays: Implication on the abundance of acetic acid and methyl formate in the interstellar medium. Planetary and Space Science, v. 149, n. SI, p. 83-93, DEC 1 2017. Web of Science Citations: 4.

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