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Pereira-da-Silva J, Mendes M, Kossoski F, Lozano AI, Rodrigues R, Jones NC, Hoffmann SV, Ferreira da Silva F. Perfluoro effect on the electronic excited states of para-benzoquinone revealed by experiment and theory. Phys Chem Chem Phys 2021; 23:2141-2153. [PMID: 33437976 DOI: 10.1039/d0cp05626j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a comprehensive study on the electronic excited states of tetrafluoro-1,4-benzoquinone, through high-resolution vacuum ultraviolet photoabsorption spectroscopy and time-dependent density functional theory calculations performed within the nuclear ensemble approach. Absolute cross section values were experimentally determined in the 3.8-10.8 eV energy range. The present experimental results represent the highest resolution data yet reported for this molecule and reveal previously unresolved spectral structures. The interpretation of the results was made in close comparison with the available data for para-benzoquinone [Jones et al., J. Chem. Phys., 2017, 146, 184303]. While the dominant absorption features for both molecules arise from analogous π* ← π transitions, some remarkable differences have been identified. The perfluoro effect manifests in different ways: shifts in band positions and cross sections, appearance of features associated with excitations to σCF* orbitals, and spectrum broadening by quenching of either vibrational or Rydberg progressions. The level of agreement between experiment and theory is very satisfactory, yet that required the inclusion of nuclear quantum effects in the calculations. We have also discussed the role of temperature on the absorption spectrum, as well as the involvement of core-excited resonances in promoting dissociative electron attachment reactions in the 3-5 eV range.
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Affiliation(s)
- J Pereira-da-Silva
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
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2
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Lozano AI, Maioli LS, Pamplona B, Romero J, Mendes M, Ferreira da Silva F, Kossoski F, Probst M, Süβ D, Bettega MHF, García G, Limão-Vieira P. Selective bond breaking of halothane induced by electron transfer in potassium collisions. Phys Chem Chem Phys 2020; 22:23837-23846. [PMID: 33073277 DOI: 10.1039/d0cp02570d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present novel experimental results of negative ion formation of halothane (C2HBrClF3) upon electron transfer from hyperthermal neutral potassium atoms (K°) in the collision energy range of 8-1000 eV. The experiments were performed in a crossed molecular beam setup allowing a comprehensive analysis of the time-of-flight (TOF) mass negative ions fragmentation pattern and a detailed knowledge of the collision dynamics in the energy range investigated. Such TOF mass spectra data show that the only negative ions formed are Br-, Cl- and F-, with a strong energy dependence in the low-energy collision region, with the bromine anion being the most abundant and sole fragment at the lowest collision energy probed. In addition, potassium cation (K+) energy loss spectra in the forward scattering direction were obtained in a hemispherical energy analyser at different K° impact energies. In order to support our experimental findings, ab initio quantum chemical calculations have been performed to help interpret the role of the electronic structure of halothane. Potential energy curves were obtained along the C-X (X = Br, Cl) coordinate to lend support to the dissociation processes yielding anion formation.
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Affiliation(s)
- A I Lozano
- Atomic and Molecular Collisions Laboratory, CEFITEC, Department of Physics, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
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3
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Kiataki MB, do N Varella MT, Bettega MHF, Kossoski F. Shape Resonances and Elastic Cross Sections in Electron Scattering by CF 3Br and CF 3I. J Phys Chem A 2020; 124:8660-8667. [PMID: 33050696 DOI: 10.1021/acs.jpca.0c07845] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Trifluoroiodomethane (CF3I) is one of the most appealing candidates for applications in plasma-based technologies in view of its many interesting advantages when compared to more standard gases such as trifluorobromomethane (CF3Br). Low-energy electrons are prone to decomposing these molecules into reactive species, and knowledge on the collision cross sections is fundamental for modeling transport and reactivity in plasma environments. Despite many studies on electron collisions with the abovementioned molecules, there are conflicting results on the assignment of shape resonances and on the magnitudes of total cross sections. Here, we try to clarify these aspects by performing ab initio electron scattering calculations. We found integral cross sections in fair agreement with the most recent measurements, in contrast to previous reports. For each molecule, we found a σCX* resonance (antibonding between the carbon and the heavy halogen) at 1 eV in CF3Br and at ∼0 eV in CF3I. Furthermore, there are three shape resonances of σCF* character; two are degenerate and account for a broad feature around 6 eV and the other one appears around 9.5 eV. We also discuss the possible role of the degenerate resonance in dissociative electron attachment reactions, as well as the impact of the heavy halogen on the cross sections and on the shape resonances.
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Affiliation(s)
- M B Kiataki
- Instituto de Fı́sica, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, São Paulo, Brazil.,Departamento de Fı́sica, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba, Paraná 81531-990, Brazil
| | - M T do N Varella
- Instituto de Fı́sica, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, São Paulo, Brazil
| | - M H F Bettega
- Departamento de Fı́sica, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba, Paraná 81531-990, Brazil
| | - F Kossoski
- Aix Marseille Université, CNRS, ICR, Marseille, France
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4
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Affiliation(s)
- F. Kossoski
- Aix Marseille University, CNRS, ICR, Marseille, France
| | - M. T. do N. Varella
- Institute of Physics, University of São Paulo, Rua do Matão 1731, 05508-090 São Paulo, Brazil
| | - M. Barbatti
- Aix Marseille University, CNRS, ICR, Marseille, France
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5
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da Costa RF, Ruivo JC, Kossoski F, Varella MTDN, Bettega MHF, Jones DB, Brunger MJ, Lima MAP. An ab initio investigation for elastic and electronically inelastic electron scattering from para-benzoquinone. J Chem Phys 2018; 149:174308. [DOI: 10.1063/1.5050622] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- R. F. da Costa
- Centro de Ciências Exatas, Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória, Espírito Santo, Brazil
- Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - J. C. Ruivo
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, Brazil
| | - F. Kossoski
- Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - M. T. do N. Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, Brazil
| | - M. H. F. Bettega
- Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná, Brazil
| | - D. B. Jones
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - M. J. Brunger
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - M. A. P. Lima
- Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
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6
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Abstract
The efficient decomposition of nitroimidazoles (NIs) by low energy electrons is believed to underlie their radiosensitizing properties. Recent dissociative electron attachment (DEA) measurements showed that methylation at the N1 site unexpectedly suppresses the electron-induced reactions in 4(5)-NI. We report theoretical results that provide a clear interpretation of that astounding finding. Around 1.5 eV, DEA reactions into several fragments are initiated by a π* resonance, not considered in previous studies. The autoionization lifetime of this anion state, which limits the predissociation dynamics, is considerably shorter in the methylated species, thereby suppressing the DEA signals. On the other hand, the lifetime of the π* resonance located around 3 eV is less affected by methylation, which explains why DEA is still observed at these energies. Our results demonstrate how even a simple methylation can significantly modify the probabilities for DEA reactions, which may be significant for NI-based cancer therapy.
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Affiliation(s)
- F Kossoski
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - M T do N Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, São Paulo, Brazil
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7
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Jones DB, da Costa RF, Kossoski F, Varella MTDN, Bettega MHF, García G, Blanco F, White RD, Lima MAP, Brunger MJ. Integral elastic, vibrational-excitation, electronic-state excitation, ionization, and total cross sections for electron scattering from para-benzoquinone. J Chem Phys 2018; 148:204305. [DOI: 10.1063/1.5028298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- D. B. Jones
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - R. F. da Costa
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
- Centro de Ciências Exatas, Departamento de Física, Universidade Federal do Espírito Santo, 29075-901 Vitória, Espírito Santo, Brazil
| | - F. Kossoski
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - M. T. do N. Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, São Paulo, Brazil
| | - M. H. F. Bettega
- Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná, Brazil
| | - G. García
- Instituto de Física Fundamental, CSIC, Serrano 113-bis, E-28006 Madrid, Spain
| | - F. Blanco
- Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040, Spain
| | - R. D. White
- College of Science and Engineering, James Cook University, Townsville, Qld 4811, Australia
| | - M. A. P. Lima
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - M. J. Brunger
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
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Jones DB, da Costa RF, Kossoski F, Varella MTDN, Bettega MHF, Ferreira da Silva F, Limão-Vieira P, García G, Lima MAP, White RD, Brunger MJ. Electron-impact electronic-state excitation of para-benzoquinone. J Chem Phys 2018; 148:124312. [DOI: 10.1063/1.5023494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- D. B. Jones
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - R. F. da Costa
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
- Centro de Ciências Exatas, Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória, Espírito Santo, Brazil
| | - F. Kossoski
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - M. T. do N. Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, São Paulo, Brazil
| | - M. H. F. Bettega
- Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná, Brazil
| | - F. Ferreira da Silva
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - P. Limão-Vieira
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - G. García
- Instituto de Fisica Fundamental, CSIC, Serrano 113-bis, E-28006 Madrid, Spain
| | - M. A. P. Lima
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - R. D. White
- College of Science and Engineering, James Cook University, Townsville, Australia
| | - M. J. Brunger
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
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Jones DB, Blanco F, García G, da Costa RF, Kossoski F, Varella MTDN, Bettega MHF, Lima MAP, White RD, Brunger MJ. Elastic scattering and vibrational excitation for electron impact onpara-benzoquinone. J Chem Phys 2017; 147:244304. [DOI: 10.1063/1.5010831] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- D. B. Jones
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - F. Blanco
- Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040, Spain
| | - G. García
- Instituto de Física Fundamental, CSIC, Serano 113-bis, E-28006 Madrid, Spain
| | - R. F. da Costa
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, São Paulo 13083-859, Brazil
- Centro de Ciências Exatas, Departamento de Física, Universidade Federal do Espírito Santo, 29075-901 Vitória, Espírito Santo, Brazil
| | - F. Kossoski
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, São Paulo 13083-859, Brazil
| | - M. T. do N. Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, São Paulo 05508-090, Brazil
| | - M. H. F. Bettega
- Departamento de Física, Universidade Federal do Paraná, CP 19044, Curitiba, Paraná 81531-990, Brazil
| | - M. A. P. Lima
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, São Paulo 13083-859, Brazil
| | - R. D. White
- College of Science and Engineering, James Cook University, Townsville, Qld 4811, Australia
| | - M. J. Brunger
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
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10
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Cornetta LM, Kossoski F, Varella MTDN. Transient anion spectra of the potential radiosensitizers 5-cyanateuracil and 5-thiocyanateuracil. J Chem Phys 2017; 147:214310. [DOI: 10.1063/1.5007050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- L. M. Cornetta
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, Brazil
| | - F. Kossoski
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
- Aix Marseille University, CNRS, ICR, Marseille, France
| | - M. T. do N. Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, Brazil
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11
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Affiliation(s)
- F. Kossoski
- Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo, Brazil
| | - M. T. do N. Varella
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, São Paulo, Brazil
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12
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Abstract
The valence anion states of the potential radiosensitisers 5-bromouracil and 5-iodouracil were investigated through elastic scattering calculations. These compounds have rich spectra of negative ion states that trigger off different mechanisms for dissociative electron attachment. For each molecule, we obtained a bound π* anion, two π* shape resonances and a low lying σ* anion state, in addition to a dipole-bound state (the latter was obtained using bound-state techniques). The σ* anion, formed by electron attachment to an anti-bonding carbon-halogen orbital, was found to have resonant character in 5-bromouracil, and bound-state character in 5-iodouracil. The present calculations place the σCBr* resonance around 0.7 eV, considerably below the energy inferred from the electron transmission data (1.3 eV). The signature of this anion state, not evident in the measurements, would be obscured by the large background arising from the dipolar interaction, not by the strong signature of the π2*, as presumed. Our results support the π2* resonance as a precursor state to dissociative electron attachment around 1.5 eV in both 5-bromouracil and 5-iodouracil, while the interplay among π1*, σ* and dipole-bound states would be expected close to 0 eV. We also discuss the suppression of the hydrogen elimination channels in these species.
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Affiliation(s)
- F Kossoski
- Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, 05314-970, São Paulo, São Paulo, Brazil.
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13
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Kossoski F, Kopyra J, Varella MTDN. Anion states and fragmentation of 2-chloroadenine upon low-energy electron collisions. Phys Chem Chem Phys 2015; 17:28958-65. [DOI: 10.1039/c5cp04967a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on a joint theoretical and experimental investigation into the electron-induced fragmentation of 2-chloroadenine, for electrons up to 12 eV. Our results suggest that 2-chloroadenine can be considered as potential radiosensitiser.
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Affiliation(s)
- F. Kossoski
- Instituto de Física
- Universidade de São Paulo
- São Paulo
- Brazil
| | - J. Kopyra
- Siedlce University
- Faculty of Science
- 08-110 Siedlce
- Poland
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14
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Abstract
We report on the shape resonance spectra of uracil, 5-fluorouracil, and 5-chlorouracil, as obtained from fixed-nuclei elastic scattering calculations performed with the Schwinger multichannel method with pseudopotentials. Our results are in good agreement with the available electron transmission spectroscopy data, and support the existence of three π∗ resonances in uracil and 5-fluorouracil. As expected, the anion states are more stable in the substituted molecules than in uracil. Since the stabilization is stronger in 5-chlorouracil, the lowest π∗ resonance in this system becomes a bound anion state. The present results also support the existence of a low-lying σCCl (*) shape resonance in 5-chlorouracil. Exploratory calculations performed at selected C-Cl bond lengths suggest that the σCCl (*) resonance could couple to the two lowest π∗ states, giving rise to a very rich dissociation dynamics. These facts would be compatible with the complex branching of the dissociative electron attachment cross sections, even though we cannot discuss any details of the vibration dynamics based only on the present fixed-nuclei results.
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Affiliation(s)
- F Kossoski
- Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, 05314-970 São Paulo, São Paulo, Brazil
| | - M H F Bettega
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-990 Curitiba, Paraná, Brazil
| | - M T do N Varella
- Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, 05314-970 São Paulo, São Paulo, Brazil
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Kopyra J, Abdoul-Carime H, Kossoski F, Varella MTDN. Electron driven reactions in sulphur containing analogues of uracil: the case of 2-thiouracil. Phys Chem Chem Phys 2014; 16:25054-61. [DOI: 10.1039/c4cp03544e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron induced fragmentation of 2-thiouracil.
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Affiliation(s)
- J. Kopyra
- Chemistry Department
- Siedlce University
- 08-110 Siedlce, Poland
| | - H. Abdoul-Carime
- Université de Lyon
- Université Lyon 1
- CNRS/IN2P3
- UMR5822
- Institut de Physique Nucléaire de Lyon
| | - F. Kossoski
- Instituto de Fisica
- Universidade de São Paulo
- 05314-970 São Paulo, Brazil
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Kossoski F, Bettega MHF. Low-energy electron scattering from the aza-derivatives of pyrrole, furan, and thiophene. J Chem Phys 2013; 138:234311. [DOI: 10.1063/1.4811218] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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