Single and double ionization of the camphor molecule excited around the C 1s edge
RATIONALE An interesting class of volatile compounds, the monoterpenes, is present in some plants although their functions are not yet fully understood. We have studied the interaction of the camphor molecule with monochromatic high-energy photons (synchrotron radiation) using time-of-flight mass sp...
| Autor principal: | Castilho, R. B. de |
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| Outros Autores: | Ramalho, Teodorico Castro, Nunez, C. V., Coutinho, Lúcia H., Santos, Antonio Carlos Fontes, Pilling, Sérgio, Lago, Alexsandre F., Silva-Moraes, M. O., Souza, Gerardo Gerson Bezerra de |
| Grau: | Artigo |
| Idioma: | English |
| Publicado em: |
Rapid Communications in Mass Spectrometry
2020
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| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/17598 |
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oai:repositorio:1-17598 |
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oai:repositorio:1-17598 Single and double ionization of the camphor molecule excited around the C 1s edge Castilho, R. B. de Ramalho, Teodorico Castro Nunez, C. V. Coutinho, Lúcia H. Santos, Antonio Carlos Fontes Pilling, Sérgio Lago, Alexsandre F. Silva-Moraes, M. O. Souza, Gerardo Gerson Bezerra de Camphor Carbon Ion Chemical Model Chemical Structure Chemistry Computer Simulation Mass Spectrometry Photon Procedures Radiation Response Synchrotron Camphor Carbon Computer Simulation Ions Mass Spectrometry Models, Chemical Models, Molecular Photons Synchrotrons RATIONALE An interesting class of volatile compounds, the monoterpenes, is present in some plants although their functions are not yet fully understood. We have studied the interaction of the camphor molecule with monochromatic high-energy photons (synchrotron radiation) using time-of-flight mass spectrometry and coincidence techniques. METHODS A commercial sample of S-camphor was admitted into the vacuum chamber, without purification, through an inlet system. Monochromatic light with energy around the C 1s edge was generated by the TGM beamline at the Brazilian Synchrotron Facility. A Wiley-McLaren mass spectrometer was used to characterize and detect the ions formed by the camphor photoionization. The data analysis was supported by energy calculations. RESULTS Although the fragmentation patterns were basically the same at 270 eV and 330 eV, it was observed that above the C 1s edge the contribution to the spectrum from lower mass/charge fragment ions increased, pointing to a higher degree of dissociation of the molecule. Projections of the PEPIPICO spectra demonstrated the existence of unstable doubly charged species. The Gibbs free energy was calculated using the Møller-Plesset perturbation theory (MP2) for the neutral, singly and doubly excited camphor molecule. CONCLUSIONS Our PEPIPICO spectrum clearly demonstrated the formation of doubly ionic dissociative species. From a slope analysis, we propose a secondary decay after a deferred charge separation mechanism in which, after a few steps, the camphor dication dissociates into C2H3 + and C3H5+. This is the main relaxation route observed at 270 eV and 330 eV. The large energy difference between the mono and the dication (of the order of 258.2 kcal/mol) may explain the experimentally observed absence of stable dications in the spectra, because their formation is disadvantaged energetically. Copyright © 2014 John Wiley & Sons, Ltd. 2020-06-15T21:48:27Z 2020-06-15T21:48:27Z 2014 Artigo https://repositorio.inpa.gov.br/handle/1/17598 10.1002/rcm.6961 en Volume 28, Número 15, Pags. 1769-1776 Restrito Rapid Communications in Mass Spectrometry |
| institution |
Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional |
| collection |
INPA-RI |
| language |
English |
| topic |
Camphor Carbon Ion Chemical Model Chemical Structure Chemistry Computer Simulation Mass Spectrometry Photon Procedures Radiation Response Synchrotron Camphor Carbon Computer Simulation Ions Mass Spectrometry Models, Chemical Models, Molecular Photons Synchrotrons |
| spellingShingle |
Camphor Carbon Ion Chemical Model Chemical Structure Chemistry Computer Simulation Mass Spectrometry Photon Procedures Radiation Response Synchrotron Camphor Carbon Computer Simulation Ions Mass Spectrometry Models, Chemical Models, Molecular Photons Synchrotrons Castilho, R. B. de Single and double ionization of the camphor molecule excited around the C 1s edge |
| topic_facet |
Camphor Carbon Ion Chemical Model Chemical Structure Chemistry Computer Simulation Mass Spectrometry Photon Procedures Radiation Response Synchrotron Camphor Carbon Computer Simulation Ions Mass Spectrometry Models, Chemical Models, Molecular Photons Synchrotrons |
| description |
RATIONALE An interesting class of volatile compounds, the monoterpenes, is present in some plants although their functions are not yet fully understood. We have studied the interaction of the camphor molecule with monochromatic high-energy photons (synchrotron radiation) using time-of-flight mass spectrometry and coincidence techniques. METHODS A commercial sample of S-camphor was admitted into the vacuum chamber, without purification, through an inlet system. Monochromatic light with energy around the C 1s edge was generated by the TGM beamline at the Brazilian Synchrotron Facility. A Wiley-McLaren mass spectrometer was used to characterize and detect the ions formed by the camphor photoionization. The data analysis was supported by energy calculations. RESULTS Although the fragmentation patterns were basically the same at 270 eV and 330 eV, it was observed that above the C 1s edge the contribution to the spectrum from lower mass/charge fragment ions increased, pointing to a higher degree of dissociation of the molecule. Projections of the PEPIPICO spectra demonstrated the existence of unstable doubly charged species. The Gibbs free energy was calculated using the Møller-Plesset perturbation theory (MP2) for the neutral, singly and doubly excited camphor molecule. CONCLUSIONS Our PEPIPICO spectrum clearly demonstrated the formation of doubly ionic dissociative species. From a slope analysis, we propose a secondary decay after a deferred charge separation mechanism in which, after a few steps, the camphor dication dissociates into C2H3 + and C3H5+. This is the main relaxation route observed at 270 eV and 330 eV. The large energy difference between the mono and the dication (of the order of 258.2 kcal/mol) may explain the experimentally observed absence of stable dications in the spectra, because their formation is disadvantaged energetically. Copyright © 2014 John Wiley & Sons, Ltd. |
| format |
Artigo |
| author |
Castilho, R. B. de |
| author2 |
Ramalho, Teodorico Castro Nunez, C. V. Coutinho, Lúcia H. Santos, Antonio Carlos Fontes Pilling, Sérgio Lago, Alexsandre F. Silva-Moraes, M. O. Souza, Gerardo Gerson Bezerra de |
| author2Str |
Ramalho, Teodorico Castro Nunez, C. V. Coutinho, Lúcia H. Santos, Antonio Carlos Fontes Pilling, Sérgio Lago, Alexsandre F. Silva-Moraes, M. O. Souza, Gerardo Gerson Bezerra de |
| title |
Single and double ionization of the camphor molecule excited around the C 1s edge |
| title_short |
Single and double ionization of the camphor molecule excited around the C 1s edge |
| title_full |
Single and double ionization of the camphor molecule excited around the C 1s edge |
| title_fullStr |
Single and double ionization of the camphor molecule excited around the C 1s edge |
| title_full_unstemmed |
Single and double ionization of the camphor molecule excited around the C 1s edge |
| title_sort |
single and double ionization of the camphor molecule excited around the c 1s edge |
| publisher |
Rapid Communications in Mass Spectrometry |
| publishDate |
2020 |
| url |
https://repositorio.inpa.gov.br/handle/1/17598 |
| _version_ |
1787144348773646336 |
| score |
11.755432 |