Electron–methane interaction model for the energy range 0.1–10000eV

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Total electron scattering cross sections for pyrazine in the energy range 10-500 eV have been measured with a new magnetically confined electron transmission-beam apparatus. Theoretical differential and integral elastic, as well as integral inelastic, cross sections have been calculated by means of a screening-corrected form of the independent-atom representation (IAM-SCAR) from 10 to 1000 eV incident electron energies. The present experimental and theoretical total cross sections show a good level of agreement, to within 10%, in the overlapping energy range. Consistency of these results with previous calculations (i.e., the R-matrix and Schwinger Multichannel methods) and elastic scattering measurements at lower energies, below 10 eV, is also discussed. © 2013 AIP Publishing LLC.

Section: Theoretical Method: the Iam-scar Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An investigation into electron scattering from pyrazine at intermediate and high energies

Sanz

Fuß

Blanco

et al. 2013

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“…Recent developments of Monte Carlo-based empirical simulations on pseudo-physiological environment allow us to model electron (and positron) tracks that result from the interaction of high energy quanta through a given tissue-equivalent material (TEM). [3][4][5][6][7] At the moment, however, the simulations are restricted to rather simplistic TEMs, [6][7][8] owing to the empirical nature of these models requiring information on the cross sections and dynamics of the underlying physicochemical processes. Therefore, the study of fundamental molecular mechanisms is of particular relevance to allow for these models to encompass increasingly (and therefore more accurate) descriptions of the physiological environment's response to radiation-induced changes.…”

Section: Introductionmentioning

confidence: 99%

Dynamic of negative ions in potassium-D-ribose collisions

Almeida

Silva

Garcı́a

et al. 2013

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We present negative ion formation from collisions of neutral potassium atoms with D-ribose (C5H10O5), the sugar unit in the DNA/RNA molecule. From the negative ion time-of-flight (TOF) mass spectra, OH− is the main fragment detected in the collision range 50-100 eV accounting on average for 50% of the total anion yield. Prominence is also given to the rich fragmentation pattern observed with special attention to O− (16 m/z) formation. These results are in sharp contrast to dissociative electron attachment experiments. The TOF mass spectra assignments show that these channels are also observed, albeit with a much lower relative intensity. Branching ratios of the most abundant fragment anions as a function of the collision energy are obtained, allowing to establish a rationale on the collision dynamics. We present negative ion formation from collisions of neutral potassium atoms with D-ribose (C 5 H 10 O 5 ), the sugar unit in the DNA/RNA molecule. From the negative ion time-of-flight (TOF) mass spectra, OH − is the main fragment detected in the collision range 50-100 eV accounting on average for 50% of the total anion yield. Prominence is also given to the rich fragmentation pattern observed with special attention to O − (16 m/z) formation. These results are in sharp contrast to dissociative electron attachment experiments. The TOF mass spectra assignments show that these channels are also observed, albeit with a much lower relative intensity. Branching ratios of the most abundant fragment anions as a function of the collision energy are obtained, allowing to establish a rationale on the collision dynamics. © 2013 AIP Publishing LLC. [http://dx

“…Also, an uncertainty of about 10% on the elastic DCSs is good enough to apply those data in the Monte Carlo simulations used to estimate energy deposition in the medium upon high-energy radiation. 48 Nevertheless, the present study reveals that, although the contribution of vibrationally inelastic processes strongly decreases with increasing incident energy at small scattering angles, as usually assumed, this contribution could increase to even above 10% at high scattering angles where the elastic DCSs attain small values. Therefore, it cannot be considered negligible if a highly precise study is needed.…”

Section: Resultsmentioning

confidence: 80%

Absolute cross sections for electron scattering from furan

Maljković

Blanco

Čurík

et al. 2012

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We report results of measurements and calculations of absolute cross sections for electron scattering from furan molecules (C 4 H 4 O). The experimental absolute differential cross sections (DCSs) for elastic electron scattering were obtained for the incident energies from 50 eV to 300 eV and for scattering angles from 20 o to 110 o , by using a crossed electron-target beam setup and the relative flow technique for calibration to the absolute scale. The calculations of the electron interaction cross sections are based on a corrected form of the independent-atom method, known as the screening corrected additivity rule (SCAR) procedure and using an improved quasifree absorption model. The latter calculations also account for rotational excitations in the approximation of a free electric dipole and were used to obtain elastic DCSs as well as total and integral elastic cross sections which are tabulated in the energy range from 10 to 10 000 eV. All SCAR calculated cross sections agree very well with both the present and previously published experimental results. Additionally, calculations based on the first Born approximation were performed to calculate both elastic and vibrationally inelastic DCSs for all the modes of furane, in the energy range from 50 eV to 300 eV. The ratios of the summed vibrational to elastic DCSs are presented and discussed. Finally, the present results for furan are compared with previously published elastic DCSs for the tetrahydrofuran molecule and discussed.