Files in this item

FilesDescriptionFormat

application/vnd.openxmlformats-officedocument.presentationml.presentation

application/vnd.openxmlformats-officedocument.presentationml.presentation1339550.pptx (6MB)
PresentationMicrosoft PowerPoint 2007

application/pdf

application/pdf3650.pdf (136kB)
AbstractPDF

Description

Title:APPLICATIONS OF H-ATOM QUANTUM-DIFFUSION REACTIONS IN SOLID PARA-HYDROGEN TO ASTROCHEMICAL STUDIES: FINDING A MYSTERIOUS LINK BETWEEN INTERSTELLAR ISOCYANIC ACID [HNCO] AND FORMAMIDE [H2NC(O)H]
Author(s):Haupa, Karolina Anna
Contributor(s):Lee, Yuan-Pern ; Tarczay, Gyorgy
Subject(s):Mini-symposium: Astrochemistry and Astrobiology in the age of ALMA
Abstract:\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.6]{cycle.eps} \end{wrapfigure} Formamide [\chem{H_2NC(O)H}], the smallest molecule containing the biologically important peptide bond, was detected in the interstellar medium (ISM) almost 50 years ago. Recent observations have shown that a strong correlation between its abundance and that of isocyanic acid [\chem{HNCO}] exists in pre- and protostellar environments. It was proposed that this correlation is due to effective synthesis of formamide from \chem{HNCO} by consecutive H-atom addition reactions.\footnote{L\`{o}pez-Sepulcre, \textit{Montly Not. Roy. Astr. Soc.} \textbf{449}, 2438–2458 (2015).} However, Nobel \textit{et al.} showed that bombardment of \chem{HNCO} ice with H atoms led no formation of formamide.\footnote{Nobel, J. A., \textit{et al.}, \textit{Astron. Astrophys.} \textbf{576}, A91 (2015).} So far, no laboratory experiment or theoretical calculations can explain the linkage between these two species.\\ We utilized the advantages of the solid \textit{para-}H$_2$ quantum host to investigate the H-atom reactions linking \chem{HNCO} and formamide. Reactions of \chem{H_2NC(O)H} with H atoms lead to \chem{H_2NCO}, and subsequently \chem{HNCO}. Further hydrogenation reactions convert some HNCO back to \chem{H_2NCO} and \chem{H_2NC(O)H}; the reaction with \chem{D_2NC(O)H} clearly showed that these reactions took place. The correlation between the abundance of \chem{HNCO} and \chem{H_2NC(O)H} can hence be understood by a dual-cycle mechanism shown in the figure, which connects the two species by a quasi-equilibrium. This mechanism and its generalized form for other molecular pairs can also play an important role in the formation of interstellar H$_2$ from H atoms.
Issue Date:2019-06-18
Publisher:International Symposium on Molecular Spectroscopy
Genre:Conference Paper / Presentation
Type:Text
Language:English
URI:http://hdl.handle.net/2142/104475
DOI:10.15278/isms.2019.TA06
Rights Information:Copyright 2019 Karolina Anna Haupa
Date Available in IDEALS:2019-07-15
2020-01-25


This item appears in the following Collection(s)

Item Statistics