Multiphoton ionization and dissociation of naphthalene at 266, 355, and 532nm

Poveda, Juan Carlos; Guerrero, Ana Luisa Guerrero; Álvarez, I.; Cisneros, C.

doi:10.1016/j.jphotochem.2010.07.031

Cited by 11 publications

(6 citation statements)

References 32 publications

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“…From the results, it was possible to observe that the interactions of molecules in the molecular mass ranges of 1616–1655 and 2096–2164 can produce clusters with two and three molecules per cluster unit, observed in the region of masses of 2867–3110 and 5139–5507, respectively. To our knowledge, MALDI-TOF-MS has been useful in determining the molecular profile distributions of heavy fractions from crude oils, but many aspects of processes taking place during the desorption and ionization remain unrevealed. , Desorption and ionization processes are very sensitive to the radiation intensities and wavelengths because the wavelength can promote either resonant or non-resonant photon absorption, as has been reported by other authors. − In the present study, it was difficult to follow the changes of molecular weight distributions because the formation of cluster darkens the analysis. From data in Table , we observe that the relative amount of mass distribution centered at 1616–1655 and 2096–2164 Da decreases as the treatment time increases, while the higher mass clusters, 2867–3110 and 5139–5507 Da, increase.…”

Section: Resultsmentioning

confidence: 62%

“…To our knowledge, MALDI-TOF-MS has been useful in determining the molecular profile distributions of heavy fractions from crude oils, but many aspects of processes taking place during the desorption and ionization remain unrevealed. 37,38 Desorption and ionization processes are very sensitive to the radiation intensities and wavelengths because the wavelength can promote either resonant or nonresonant photon absorption, as has been reported by other authors. 39−42 In the present study, it was difficult to follow the changes of molecular weight distributions because the formation of cluster darkens the analysis.…”

Section: Resultsmentioning

confidence: 66%

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Molecular Changes in Asphaltenes within H₂ Plasma

et al. 2014

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In the present work, the chemical changes in asphaltenes, solid residues, when they are treated with hydrogen plasma were analyzed. H 2 plasma was characterized by the presence of electrons, H + and H 2 + ions, at kinetic energies as low as 30 eV. These species can interact with the asphaltenes to produce changes in the chemical structure by different mechanisms such as bond cleavage, recombination, and condensation. Asphaltene samples were exposed to different treatment times (up to 120 min). The plasma was characterized by optical emission spectroscopy (OES) as well as by the different products created in the reactions of asphaltenes. The presence of C + , CH + , C 2 + , NH + , and V + was confirmed. Spectroscopic techniques such as Fourier transform infrared spectroscopy (FT-IR), matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS), nuclear magnetic resonance spectroscopy ( 1 H NMR and 13 C NMR), and X-ray diffractometry (XRD) were used to characterize the chemical composition of asphaltenes at the different treatment times. Chemical changes were analyzed from the molecular structural parameters calculated by the above-mentioned spectroscopic techniques. Possible changes in the asphaltene cluster structures were analyzed using XRD. This work explores the application of plasma technologies to modify the chemical composition of asphaltenes and obtain valuable chemical products resulting from a plasma treatment process.

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Section: Resultsmentioning

confidence: 62%

Section: Resultsmentioning

confidence: 66%

Molecular Changes in Asphaltenes within H₂ Plasma

et al. 2014

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“…The charged residues resulting from the fragmentation were accelerated in a spectrometer arm and identified. This multiphoton excitation method has since been implemented in several experimental setups [56,59] …”

Section: Comparison With Experimental Resultsmentioning

confidence: 99%

“…This multiphoton excitation method has since been implemented in several experimental setups. [56,59] Figure 6 shows a typical spectrum obtained at high laser intensity. Similarly to the Vinitha et al experiment, [56] the 2H loss channel is much lower than the H and 3H loss channels.…”

Section: Vinitha Et Al Experimentsmentioning

confidence: 99%

Competition between Loss of H₂ versus H+H in the Fragmentation of the Fluorene Cation

Désesquelles,

Domin,

et al. 2023

ChemPhysChem

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The fluorene cation is a frequently studied molecule in the context of fragmentation experiments. This is because of its potential role in interstellar chemistry, notably as a precursor of PAH cages. In this paper, we analyze H, H+, H2 and H+2 losses from the fluorene cation using the SMF (Statistical Molecular Fragmentation) model. We calculate the probabilities of all the 534 possible fragmentation channels as a function of the excitation energy, up to the loss of three hydrogens. Four different types of hydrogen atom pairings (from the same carbon, from the same ring, from different rings and across‐the‐bay) have been tested in order to determine which types contribute to the actual production of hydrogen molecules. The simulated breakdown curves are in very good agreement with different experimental results when same ring pairing is taken into account. It was possible to deduce from the model the locations of the emitted H, H+, H2 and H+2 species.

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“…A GM 12 consists of spatially averaged continuity equations for each species, including naphthalene. The threshold energies of naphthalene reactions are determined according to ref 16 and are presented in Table 1.…”

Section: Simulation Model Componentsmentioning

confidence: 99%

Numeric Model for Assessment of Naphthalene Conversion through Ionization Reactions in a Microwave Air Plasma Torch

Pilatau

Medeiros²,

Sobrinho

et al. 2016

Energy Fuels

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In this study, the authors have presented a numeric model (NM) for application to naphthalene (C10H8) conversion via ionization reaction in a microwave air plasma torch. The NM has included a pressure-independent enhanced electron energy distribution function (EEDF) and cross-section calculation, enhanced by a new formula of phase shift determination. Based on the validated NM, electron density n e and O 2 +, O –, C 10 H 8, N 2, and O 2 particles densities were calculated, as well as the conversion rate of C10H8 molecules was predicted. The predicted results showed that the ionization impact on C10H8 molecules conversion has not exceeded 0.81 × 10–10%. Based on the calculated collision cross-section of each species (O2, N2, and C10H8) of carrier gas, the authors suggested using cubic polynomial approximations of the cross-section curves with R-Square (COD) parameter R 2 = 99%. MW power increasing in the range 1.75–20 kW has raised the electron density in the range (0.5–4.5) × 1012 m–3. The maximal effect of electron density decreasing with pressure increasing was simulated at values of MW power greater than 7.5 kW. Herewith, pressure increasing and MW power increasing have not had any significant effect on the average electron energy.

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Multiphoton ionization and dissociation of naphthalene at 266, 355, and 532nm

Cited by 11 publications

References 32 publications

Molecular Changes in Asphaltenes within H₂ Plasma

Molecular Changes in Asphaltenes within H₂ Plasma

Competition between Loss of H₂ versus H+H in the Fragmentation of the Fluorene Cation

Numeric Model for Assessment of Naphthalene Conversion through Ionization Reactions in a Microwave Air Plasma Torch

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Multiphoton ionization and dissociation of naphthalene at 266, 355, and 532nm

Cited by 11 publications

References 32 publications

Molecular Changes in Asphaltenes within H2 Plasma

Molecular Changes in Asphaltenes within H2 Plasma

Competition between Loss of H2 versus H+H in the Fragmentation of the Fluorene Cation

Numeric Model for Assessment of Naphthalene Conversion through Ionization Reactions in a Microwave Air Plasma Torch

Contact Info

Product

Resources

About

Molecular Changes in Asphaltenes within H₂ Plasma

Molecular Changes in Asphaltenes within H₂ Plasma

Competition between Loss of H₂ versus H+H in the Fragmentation of the Fluorene Cation