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Sulfur Molecules in Space by X-rays: A Computational Study

[Image: see text] X-ray astronomy lacks high resolution spectra of interstellar dust analogues and molecules, severely hampering interstellar medium studies based on upcoming X-ray missions. Various theoretical approaches may be used to address this problem, but they must first be shown to reproduce...

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Autores principales: Bilalbegović, Goranka, Maksimović, Aleksandar, Valencic, Lynne A., Lehtola, Susi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2021
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028330/
https://www.ncbi.nlm.nih.gov/pubmed/33842801
http://dx.doi.org/10.1021/acsearthspacechem.0c00238
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author Bilalbegović, Goranka
Maksimović, Aleksandar
Valencic, Lynne A.
Lehtola, Susi
author_facet Bilalbegović, Goranka
Maksimović, Aleksandar
Valencic, Lynne A.
Lehtola, Susi
author_sort Bilalbegović, Goranka
collection PubMed
description [Image: see text] X-ray astronomy lacks high resolution spectra of interstellar dust analogues and molecules, severely hampering interstellar medium studies based on upcoming X-ray missions. Various theoretical approaches may be used to address this problem, but they must first be shown to reproduce reliable spectra compared to the experiment. In this work, we calculate the sulfur K edge X-ray absorption spectra of H(2)S, SO(2), and OCS, whose spectra are already known from X-ray experiments and predict the X-ray spectrum of CS, which as far as we are aware has not been measured, thereby hampering its detection by X-ray telescopes. We chose these four molecules as the astrochemistry of sulfur is an unsolved problem and as the four molecules are already known to exist in space. We consider three types of methods for modeling the X-ray spectra: more accurate calculations with the algebraic-diagrammatic construction (ADC) and the CC2, CCSD, and CC3 coupled cluster (CC) approaches as well as more affordable ones with transition potential density functional theory (TP-DFT). A comparison of our computational results to previously reported experimental spectra shows that the core–valence separation (CVS) approaches CVS-ADC(2)-x and CVS-CC3 generally yield a good qualitative level of agreement with the experiment, suggesting that they can be used for interpreting measured spectra, while the TP-DFT method is not reliable for these molecules. However, quantitative agreement with the experiment is still outside the reach of the computational methods studied in this work.
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spelling pubmed-80283302021-04-08 Sulfur Molecules in Space by X-rays: A Computational Study Bilalbegović, Goranka Maksimović, Aleksandar Valencic, Lynne A. Lehtola, Susi ACS Earth Space Chem [Image: see text] X-ray astronomy lacks high resolution spectra of interstellar dust analogues and molecules, severely hampering interstellar medium studies based on upcoming X-ray missions. Various theoretical approaches may be used to address this problem, but they must first be shown to reproduce reliable spectra compared to the experiment. In this work, we calculate the sulfur K edge X-ray absorption spectra of H(2)S, SO(2), and OCS, whose spectra are already known from X-ray experiments and predict the X-ray spectrum of CS, which as far as we are aware has not been measured, thereby hampering its detection by X-ray telescopes. We chose these four molecules as the astrochemistry of sulfur is an unsolved problem and as the four molecules are already known to exist in space. We consider three types of methods for modeling the X-ray spectra: more accurate calculations with the algebraic-diagrammatic construction (ADC) and the CC2, CCSD, and CC3 coupled cluster (CC) approaches as well as more affordable ones with transition potential density functional theory (TP-DFT). A comparison of our computational results to previously reported experimental spectra shows that the core–valence separation (CVS) approaches CVS-ADC(2)-x and CVS-CC3 generally yield a good qualitative level of agreement with the experiment, suggesting that they can be used for interpreting measured spectra, while the TP-DFT method is not reliable for these molecules. However, quantitative agreement with the experiment is still outside the reach of the computational methods studied in this work. American Chemical Society 2021-02-24 2021-03-18 /pmc/articles/PMC8028330/ /pubmed/33842801 http://dx.doi.org/10.1021/acsearthspacechem.0c00238 Text en © 2021 The Authors. Published by American Chemical Society Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Bilalbegović, Goranka
Maksimović, Aleksandar
Valencic, Lynne A.
Lehtola, Susi
Sulfur Molecules in Space by X-rays: A Computational Study
title Sulfur Molecules in Space by X-rays: A Computational Study
title_full Sulfur Molecules in Space by X-rays: A Computational Study
title_fullStr Sulfur Molecules in Space by X-rays: A Computational Study
title_full_unstemmed Sulfur Molecules in Space by X-rays: A Computational Study
title_short Sulfur Molecules in Space by X-rays: A Computational Study
title_sort sulfur molecules in space by x-rays: a computational study
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028330/
https://www.ncbi.nlm.nih.gov/pubmed/33842801
http://dx.doi.org/10.1021/acsearthspacechem.0c00238
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