Cross sections for electron scattering by formaldehyde and pyrimidine in the low- and intermediate-energy ranges

Ferraz, J. R.; Santos, A. S.; Souza, Gabriel L. C. de; Zanelato, A. I.; Alves, T. R. M.; Lee, M.-T.; Brescansin, L. M.; Lucchese, Robert R.; Machado, L. E.

doi:10.1103/physreva.87.032717

Cited by 24 publications

(12 citation statements)

References 46 publications

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“…Moreover, two shape resonances, centered at 3.5 eV and 15 eV, respectively, were identified. The one located at 3.5 eV is a 2 A resonance corresponding to the 2 B 1 shape resonance in formaldehyde [47], whereas the broad structure located at about 15 eV is a 2 A resonance which corresponds to the 2 E resonance in ammonia. Considering that the formamide molecule is roughly a union of formaldehyde and ammonia, the observed correspondence is very interesting and clearly indicates that the recent investigation on electron interaction with small building blocks, instead of with larger biomolecules itself, is relevant.…”

Section: Discussionmentioning

confidence: 97%

“…Similar to formaldehyde, formamide is also strongly polar and has an empty π * orbital and therefore supports a shape resonance. Probably, the feature located at about 3.5 eV corresponds to the one seen in the 2 B 1 continuum channel of formaldehyde [47], whereas the broad resonance feature at about 15 eV corresponds to that 2 E shape resonance seen in ammonia.…”

Section: B Formamidementioning

confidence: 93%

“…The theory used in this work is essentially the same as in several previous works [5,46,47]. Briefly, a complex optical potential given by (2) was used to represent the electron-target interaction.…”

Section: Theorymentioning

confidence: 99%

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Electron collisions with ammonia and formamide in the low- and intermediate-energy ranges

et al. 2014

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We report an investigation on electron collisions with two nitrogen-containing compounds, namely ammonia (NH 3 ) and formamide (NH 2 CHO). For ammonia, both theoretical and experimental differential, integral, and momentum-transfer cross sections, as well as calculated grand-total and total absorption cross sections, are reported in the 50-500 eV incident energy range. Calculated results of various cross sections are also reported for energies below 50 eV. Experimentally, angular distributions of the scattered electrons were measured using a crossed electron beam-molecular beam geometry and then converted to absolute differential cross sections using the relative flow technique. Absolute integral and momentum-transfer cross sections for elastic e − -ammonia scattering were also derived from the measured differential cross sections. For formamide, only theoretical cross sections are presented in the 1-500 eV incident energy range. A single-center-expansion technique combined with the method of Padé was used in our calculations. For both targets, our calculated cross sections are compared with the present measured data and with the theoretical and experimental data available in the literature and show generally good agreement. Moreover, for formamide, two shape resonances located at 3.5 eV and 15 eV which correspond to the continuum 2 A and 2 A scattering symmetries, respectively, are identified. The former can be associated to the 2 B 1 shape resonance in formaldehyde located at around 2.5 eV, whereas the latter can be related to the 2 E resonance in ammonia at about 10 eV. Such correspondence is very interesting and so supports the investigation on electron interaction with small building blocks, instead of with larger biomolecules.

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Section: Discussionmentioning

confidence: 97%

Section: B Formamidementioning

confidence: 93%

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Electron collisions with ammonia and formamide in the low- and intermediate-energy ranges

et al. 2014

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“…In the recent past, this method was successfully applied by our group to treat electron collisions with ethane, propane, and pyrimidine [20][21][22]. In this work, we extend its application to DME.…”

Section: Theory and Numerical Proceduresmentioning

confidence: 99%

Cross sections for electron collisions with dimethyl ether

et al. 2013

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We report a joint theoretical-experimental investigation of electron collision with dimethyl ether (DME) in the low-and intermediate-energy ranges. Experimental absolute differential, integral, and momentum-transfer cross sections for elastic e − -DME scattering are reported in the 100-1000 eV energy range. Our measurements were performed using a crossed electron-beam-molecular-beam geometry. The angular distribution of the scattered electrons was converted to absolute cross section using the relative flow technique. Theoretically, elastic differential, integral, and momentum-transfer cross sections, as well as the grand-total and total absorption cross sections for electron collision with DME are calculated in the 1-1000 eV energy range. A single-center-expansion technique combined with the Padé approximant method is used in our calculations. A comparison between the present experimental and theoretical data shows very good agreement. Moreover, comparison with theoretical and experimental data for e − -ethanol (an isomer of DME) scattering shows interesting isomeric effects.

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“…In particular, the diazines, namely, pyrazine, pyrimidine, and pyridazine, present three π * resonances as reported by Nenner and Schulz 5 and by several other authors. [6][7][8][9][10][11] Halogenated pyrimidines represent an important class of molecules due to the fact that they are building blocks of drugs used in cancer treatment. It has been known for decades that the incorporation of halogenated pyrimidines in the DNA to replace thymidine sensitizes the cell in the radiotherapy of tumors.…”

Section: Introductionmentioning

confidence: 99%

Shape resonances in low-energy-electron collisions with halopyrimidines

Barbosa

Bettega

2013

The Journal of Chemical Physics

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We report calculated cross sections for elastic collisions of low-energy electrons with halopyrimidines, namely, 2-chloro, 2-bromo, and 5-bromopyrimidine. We employed the Schwinger multichannel method with pseudopotentials to compute the cross sections in the static-exchange and static-exchange plus polarization levels of approximation for energies up to 10 eV. We found four shape resonances for each molecule: three of π* nature localized on the ring and one of σ* nature localized along the carbon-halogen bond. We compared the calculated positions of the resonances with the electron transmission spectroscopy data measured by Modelli et al. [J. Phys. Chem. A 115, 10775 (2011)]. In general the agreement between theory and experiment is good. In particular, our results show the existence of a π* temporary anion state of A2 symmetry for all three halopyrimidines, in agreement with the dissociative electron attachment spectra also reported by Modelli et al. [J. Phys. Chem. A 115, 10775 (2011)].

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Cross sections for electron scattering by formaldehyde and pyrimidine in the low- and intermediate-energy ranges

Cited by 24 publications

References 46 publications

Electron collisions with ammonia and formamide in the low- and intermediate-energy ranges

Electron collisions with ammonia and formamide in the low- and intermediate-energy ranges

Cross sections for electron collisions with dimethyl ether

Shape resonances in low-energy-electron collisions with halopyrimidines

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