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Electronic State Spectroscopy of Nitromethane and Nitroethane

[Image: see text] High-resolution photoabsorption cross-sections in the 3.7–10.8 eV energy range are reinvestigated for nitromethane (CH(3)NO(2)), while for nitroethane (C(2)H(5)NO(2)), they are reported for the first time. New absorption features are observed for both molecules which have been assi...

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Autores principales: Dalagnol, Luiz V. S., Bettega, Márcio H. F., Jones, Nykola C., Hoffmann, Søren V., Souza Barbosa, Alessandra, Limão-Vieira, Paulo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2023
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9940216/
https://www.ncbi.nlm.nih.gov/pubmed/36730450
http://dx.doi.org/10.1021/acs.jpca.2c08023
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author Dalagnol, Luiz V. S.
Bettega, Márcio H. F.
Jones, Nykola C.
Hoffmann, Søren V.
Souza Barbosa, Alessandra
Limão-Vieira, Paulo
author_facet Dalagnol, Luiz V. S.
Bettega, Márcio H. F.
Jones, Nykola C.
Hoffmann, Søren V.
Souza Barbosa, Alessandra
Limão-Vieira, Paulo
author_sort Dalagnol, Luiz V. S.
collection PubMed
description [Image: see text] High-resolution photoabsorption cross-sections in the 3.7–10.8 eV energy range are reinvestigated for nitromethane (CH(3)NO(2)), while for nitroethane (C(2)H(5)NO(2)), they are reported for the first time. New absorption features are observed for both molecules which have been assigned to vibronic excitations of valence, Rydberg, and mixed valence-Rydberg characters. In comparison with nitromethane, nitroethane shows mainly broad absorption bands with diffuse structures, which can be interpreted as a result of the side-chain effect contributing to an increased number of internal degrees of freedom. New theoretical quantum chemical calculations performed at the time-dependent density functional theory (TD-DFT) level were used to qualitatively help interpret the recorded photoabsorption spectra. From the photoabsorption cross-sections, photolysis lifetimes in the terrestrial atmosphere have been obtained for both compounds. Relevant internal conversion from Rydberg to valence character is noted for both molecules, while the nuclear dynamics of CH(3)NO(2) and C(2)H(5)NO(2) along the C–N reaction coordinate have been evaluated through potential energy curves at the TD-DFT level of theory, showing that the pre-dissociative character is more prevalent in nitromethane than in nitroethane.
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spelling pubmed-99402162023-02-21 Electronic State Spectroscopy of Nitromethane and Nitroethane Dalagnol, Luiz V. S. Bettega, Márcio H. F. Jones, Nykola C. Hoffmann, Søren V. Souza Barbosa, Alessandra Limão-Vieira, Paulo J Phys Chem A [Image: see text] High-resolution photoabsorption cross-sections in the 3.7–10.8 eV energy range are reinvestigated for nitromethane (CH(3)NO(2)), while for nitroethane (C(2)H(5)NO(2)), they are reported for the first time. New absorption features are observed for both molecules which have been assigned to vibronic excitations of valence, Rydberg, and mixed valence-Rydberg characters. In comparison with nitromethane, nitroethane shows mainly broad absorption bands with diffuse structures, which can be interpreted as a result of the side-chain effect contributing to an increased number of internal degrees of freedom. New theoretical quantum chemical calculations performed at the time-dependent density functional theory (TD-DFT) level were used to qualitatively help interpret the recorded photoabsorption spectra. From the photoabsorption cross-sections, photolysis lifetimes in the terrestrial atmosphere have been obtained for both compounds. Relevant internal conversion from Rydberg to valence character is noted for both molecules, while the nuclear dynamics of CH(3)NO(2) and C(2)H(5)NO(2) along the C–N reaction coordinate have been evaluated through potential energy curves at the TD-DFT level of theory, showing that the pre-dissociative character is more prevalent in nitromethane than in nitroethane. American Chemical Society 2023-02-02 /pmc/articles/PMC9940216/ /pubmed/36730450 http://dx.doi.org/10.1021/acs.jpca.2c08023 Text en © 2023 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/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 Dalagnol, Luiz V. S.
Bettega, Márcio H. F.
Jones, Nykola C.
Hoffmann, Søren V.
Souza Barbosa, Alessandra
Limão-Vieira, Paulo
Electronic State Spectroscopy of Nitromethane and Nitroethane
title Electronic State Spectroscopy of Nitromethane and Nitroethane
title_full Electronic State Spectroscopy of Nitromethane and Nitroethane
title_fullStr Electronic State Spectroscopy of Nitromethane and Nitroethane
title_full_unstemmed Electronic State Spectroscopy of Nitromethane and Nitroethane
title_short Electronic State Spectroscopy of Nitromethane and Nitroethane
title_sort electronic state spectroscopy of nitromethane and nitroethane
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9940216/
https://www.ncbi.nlm.nih.gov/pubmed/36730450
http://dx.doi.org/10.1021/acs.jpca.2c08023
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