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Gustavo Garcia - One of the best experts on this subject based on the ideXlab platform.
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total electron Scattering Cross Sections from thiophene for the 1 300 ev impact energy range
Journal of Chemical Physics, 2018Co-Authors: A I Lozano, Alexandra Loupas, Francisco J Blanco, J D Gorfinkiel, Gustavo GarciaAbstract:Experimental electron Scattering Cross Sections for thiophene in the impact energy range from 1 to 300 eV have been measured with a magnetically confined electron transmission-beam apparatus. Random uncertainty limits have been estimated to be less than 5%, and systematic errors derived from acceptance angle limitations have also been identified and evaluated. Experimental values are compared with our previous low energy (1-15 eV) R-matrix and intermediate/high energy (15-300 eV) IAM-SCAR+I calculations finding reasonable agreement, within the combined uncertainty limits. Some of the low energy shape and core-excited resonances predicted by previous calculations are experimentally confirmed in this study.
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screening corrections for the interference contributions to the electron and positron Scattering Cross Sections from polyatomic molecules
Chemical Physics Letters, 2016Co-Authors: Francisco J Blanco, L Ellisgibbings, Gustavo GarciaAbstract:Abstract An improvement of the screening-corrected Additivity Rule (SCAR) is proposed for calculating electron and positron Scattering Cross Sections from polyatomic molecules within the independent atom model (IAM), following the analysis of numerical solutions to the three-dimensional Lippmann–Schwinger equation for multicenter potentials. Interference contributions affect all the considered energy range (1–300 eV); the lower energies where the atomic screening is most effective and higher energies, where interatomic distances are large compared to total Cross Sections and electron wavelengths. This correction to the interference terms provides a significant improvement for both total and differential elastic Cross Sections at these energies.
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electron Scattering Cross Sections from anthracene over a broad energy range 0 00001 10 000 ev
Applied Radiation and Isotopes, 2014Co-Authors: A G Sanz, Francisco J Blanco, Gustavo Garcia, F A Gianturco, Martina Fuss, F Carelli, F SebastianelliAbstract:We report a computational investigation of electron Scattering by anthracene (C14H10) in the gas phase. Integral and differential Cross Sections have been calculated by employing two distinct ab-initio quantum Scattering methods: the symmetry adapted–single centre expansion method (ePOLYSCAT) and a screening corrected form of the independent atom model (IAM–SCAR) at low and high energies, respectively. After a detailed evaluation of the current results, we present a complete set of integral Scattering Cross Sections from 0.00001 to 10,000 eV.
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electron Scattering Cross Sections from hcn over a broad energy range 0 1 10 000 ev influence of the permanent dipole moment on the Scattering process
Journal of Chemical Physics, 2012Co-Authors: A G Sanz, Francisco J Blanco, F A Gianturco, Martina Fuss, F Sebastianelli, Gustavo GarciaAbstract:We report theoretical integral and differential Cross Sections for electron Scattering from hydrogen cyanide derived from two ab initio Scattering potential methods. For low energies (0.1–100 eV), we have used the symmetry adapted-single centre expansion method using a multichannel Scattering formulation of the problem. For intermediate and high energies (10–10 000 eV), we have applied an optical potential method based on a screening corrected independent atom representation. Since HCN is a strong polar molecule, further dipole-induced excitations have been calculated in the framework of the first Born approximation and employing a transformation to a space-fixed reference frame of the calculated K-matrix elements. Results are compared with experimental data available in the literature and a complete set of recommended integral elastic, inelastic, and total Scattering Cross Sections is provided from 0.1 to 10 000 eV.
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electron Scattering Cross Sections for collisions with tetrahydrofuran from 50 to 5000 ev
Physical Review A, 2009Co-Authors: Martina Fuss, Francisco J Blanco, Gustavo Garcia, A Munoz, J C Oller, P Limaovieira, M J Brunger, Diogo AlmeidaAbstract:de Educacion y Ciencia Plan Nacional de Fisica, This study has been partially supported by the following research projects and institutions: Ministerio Project No. FIS2006-00702, Consejo de Seguridad Nuclear CSN, European Science Foundation COST Action CM0601 and EIPAM Project, Acciones Integradas Hispano-Portuguesas Project No. HP2006-0042
A I Lozano - One of the best experts on this subject based on the ideXlab platform.
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electron Scattering Cross Sections from nitrobenzene in the energy range 0 4 1000 ev the role of dipole interactions in measurements and calculations
Physical Chemistry Chemical Physics, 2020Co-Authors: L Alvarez, A I Lozano, A Munoz, J C Oller, P Limaovieira, F M S Costa, Francisco Garcia Blanco, R D White, M J BrungerAbstract:Absolute total electron Scattering Cross Sections (TCS) for nitrobenzene molecules with impact energies from 0.4 to 1000 eV have been measured by means of two different electron-transmission experimental arrangements. For the lower energies (0.4–250 eV) a magnetically confined electron beam system has been used, while for energies above 100 eV a linear beam transmission technique with high angular resolution allowed accurate measurements up to 1000 eV impact energy. In both cases random uncertainties were maintained below 5–8%. Systematic errors arising from the angular and energy resolution limits of each apparatus are analysed in detail and quantified with the help of our theoretical calculations. Differential elastic and integral elastic, excitation and ionisation as well as momentum transfer Cross Sections have been calculated, for the whole energy range considered here, by using an independent atom model in combination with the screening corrected additivity rule method including interference effects (IAM-SCARI). Due to the significant permanent dipole moment of nitrobenzene, additional differential and integral rotational excitation Cross Sections have been calculated in the framework of the Born approximation. If we ignore the rotational excitations, our calculated total Cross section agrees well with our experimental results for impact energies above 15 eV. Additionally, they overlap at 10 eV with the low energy Schwinger Multichannel method with Pseudo Potentials (SMCPP) calculation available in the literature (L. S. Maioli and M. H. F. Bettega, J. Chem. Phys., 2017, 147, 164305). We find a broad feature in the experimental TCS at around 1.0 eV, which has been related to the formation of the NO2− anion and assigned to the π*(b1) resonance, according to previous mass spectra available in the literature. Other local maxima in the TCSs are found at 4.0 ± 0.2 and 5.0 ± 0.2 eV and are assigned to core excited resonances leading to the formation of the NO2− and O2− anions, respectively. Finally, for energies below 10 eV, differences found between the present measurements, the SMCPP calculation and our previous data for non-polar benzene have revealed the importance of accurately calculating the rotational excitation contribution to the TCS before comparing theoretical and experimental data. This comparison suggests that our dipole-Born calculation for nitrobenzene overestimates the magnitude of the rotational excitation Cross Sections below 10 eV.
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total electron Scattering Cross Sections from thiophene for the 1 300 ev impact energy range
Journal of Chemical Physics, 2018Co-Authors: A I Lozano, Alexandra Loupas, Francisco J Blanco, J D Gorfinkiel, Gustavo GarciaAbstract:Experimental electron Scattering Cross Sections for thiophene in the impact energy range from 1 to 300 eV have been measured with a magnetically confined electron transmission-beam apparatus. Random uncertainty limits have been estimated to be less than 5%, and systematic errors derived from acceptance angle limitations have also been identified and evaluated. Experimental values are compared with our previous low energy (1-15 eV) R-matrix and intermediate/high energy (15-300 eV) IAM-SCAR+I calculations finding reasonable agreement, within the combined uncertainty limits. Some of the low energy shape and core-excited resonances predicted by previous calculations are experimentally confirmed in this study.
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total electron Scattering Cross Sections from para benzoquinone in the energy range 1 200 ev
Physical Chemistry Chemical Physics, 2018Co-Authors: A I Lozano, J C Oller, P Limaovieira, D B Jones, R F Da Costa, M Do T N Varella, M H F Bettega, Ferreira F Da Silva, Marco A P LimaAbstract:Total electron Scattering Cross Sections, from para-benzoquinone, for impact energies ranging between 1 to 200 eV, have been obtained by measuring the attenuation of a linear electron beam under magnetic confinement conditions. Random uncertainty limits on these values have been found to be within 5%. Systematic errors, due to the axial magnetic beam conditions in combination with the acceptance angle of the detector, have been evaluated by integrating our calculated independent atom model with the screening corrected additivity rule and interference term elastic differential Cross Sections over that detection acceptance angle. Our previous calculations and measurements on this molecule (Jones et al., J. Chem. Phys., 2018, 148, 124312 and J. Chem. Phys., 2018, 148, 204305), have been compiled and complemented with new elastic and inelastic Scattering Cross section calculations in order to obtain a comprehensive Cross section data base, within the considered energy range, for modelling purposes. The self-consistency of the present data set has been evaluated by simulating the electron transport of 15 eV electrons in para-benzoquinone, and comparing those results with the observed transmitted intensity distribution.
Francisco J Blanco - One of the best experts on this subject based on the ideXlab platform.
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total electron Scattering Cross Sections from thiophene for the 1 300 ev impact energy range
Journal of Chemical Physics, 2018Co-Authors: A I Lozano, Alexandra Loupas, Francisco J Blanco, J D Gorfinkiel, Gustavo GarciaAbstract:Experimental electron Scattering Cross Sections for thiophene in the impact energy range from 1 to 300 eV have been measured with a magnetically confined electron transmission-beam apparatus. Random uncertainty limits have been estimated to be less than 5%, and systematic errors derived from acceptance angle limitations have also been identified and evaluated. Experimental values are compared with our previous low energy (1-15 eV) R-matrix and intermediate/high energy (15-300 eV) IAM-SCAR+I calculations finding reasonable agreement, within the combined uncertainty limits. Some of the low energy shape and core-excited resonances predicted by previous calculations are experimentally confirmed in this study.
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screening corrections for the interference contributions to the electron and positron Scattering Cross Sections from polyatomic molecules
Chemical Physics Letters, 2016Co-Authors: Francisco J Blanco, L Ellisgibbings, Gustavo GarciaAbstract:Abstract An improvement of the screening-corrected Additivity Rule (SCAR) is proposed for calculating electron and positron Scattering Cross Sections from polyatomic molecules within the independent atom model (IAM), following the analysis of numerical solutions to the three-dimensional Lippmann–Schwinger equation for multicenter potentials. Interference contributions affect all the considered energy range (1–300 eV); the lower energies where the atomic screening is most effective and higher energies, where interatomic distances are large compared to total Cross Sections and electron wavelengths. This correction to the interference terms provides a significant improvement for both total and differential elastic Cross Sections at these energies.
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electron Scattering Cross Sections from anthracene over a broad energy range 0 00001 10 000 ev
Applied Radiation and Isotopes, 2014Co-Authors: A G Sanz, Francisco J Blanco, Gustavo Garcia, F A Gianturco, Martina Fuss, F Carelli, F SebastianelliAbstract:We report a computational investigation of electron Scattering by anthracene (C14H10) in the gas phase. Integral and differential Cross Sections have been calculated by employing two distinct ab-initio quantum Scattering methods: the symmetry adapted–single centre expansion method (ePOLYSCAT) and a screening corrected form of the independent atom model (IAM–SCAR) at low and high energies, respectively. After a detailed evaluation of the current results, we present a complete set of integral Scattering Cross Sections from 0.00001 to 10,000 eV.
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electron Scattering Cross Sections from hcn over a broad energy range 0 1 10 000 ev influence of the permanent dipole moment on the Scattering process
Journal of Chemical Physics, 2012Co-Authors: A G Sanz, Francisco J Blanco, F A Gianturco, Martina Fuss, F Sebastianelli, Gustavo GarciaAbstract:We report theoretical integral and differential Cross Sections for electron Scattering from hydrogen cyanide derived from two ab initio Scattering potential methods. For low energies (0.1–100 eV), we have used the symmetry adapted-single centre expansion method using a multichannel Scattering formulation of the problem. For intermediate and high energies (10–10 000 eV), we have applied an optical potential method based on a screening corrected independent atom representation. Since HCN is a strong polar molecule, further dipole-induced excitations have been calculated in the framework of the first Born approximation and employing a transformation to a space-fixed reference frame of the calculated K-matrix elements. Results are compared with experimental data available in the literature and a complete set of recommended integral elastic, inelastic, and total Scattering Cross Sections is provided from 0.1 to 10 000 eV.
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electron Scattering Cross Sections for collisions with tetrahydrofuran from 50 to 5000 ev
Physical Review A, 2009Co-Authors: Martina Fuss, Francisco J Blanco, Gustavo Garcia, A Munoz, J C Oller, P Limaovieira, M J Brunger, Diogo AlmeidaAbstract:de Educacion y Ciencia Plan Nacional de Fisica, This study has been partially supported by the following research projects and institutions: Ministerio Project No. FIS2006-00702, Consejo de Seguridad Nuclear CSN, European Science Foundation COST Action CM0601 and EIPAM Project, Acciones Integradas Hispano-Portuguesas Project No. HP2006-0042
M J Brunger - One of the best experts on this subject based on the ideXlab platform.
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electron Scattering Cross Sections from nitrobenzene in the energy range 0 4 1000 ev the role of dipole interactions in measurements and calculations
Physical Chemistry Chemical Physics, 2020Co-Authors: L Alvarez, A I Lozano, A Munoz, J C Oller, P Limaovieira, F M S Costa, Francisco Garcia Blanco, R D White, M J BrungerAbstract:Absolute total electron Scattering Cross Sections (TCS) for nitrobenzene molecules with impact energies from 0.4 to 1000 eV have been measured by means of two different electron-transmission experimental arrangements. For the lower energies (0.4–250 eV) a magnetically confined electron beam system has been used, while for energies above 100 eV a linear beam transmission technique with high angular resolution allowed accurate measurements up to 1000 eV impact energy. In both cases random uncertainties were maintained below 5–8%. Systematic errors arising from the angular and energy resolution limits of each apparatus are analysed in detail and quantified with the help of our theoretical calculations. Differential elastic and integral elastic, excitation and ionisation as well as momentum transfer Cross Sections have been calculated, for the whole energy range considered here, by using an independent atom model in combination with the screening corrected additivity rule method including interference effects (IAM-SCARI). Due to the significant permanent dipole moment of nitrobenzene, additional differential and integral rotational excitation Cross Sections have been calculated in the framework of the Born approximation. If we ignore the rotational excitations, our calculated total Cross section agrees well with our experimental results for impact energies above 15 eV. Additionally, they overlap at 10 eV with the low energy Schwinger Multichannel method with Pseudo Potentials (SMCPP) calculation available in the literature (L. S. Maioli and M. H. F. Bettega, J. Chem. Phys., 2017, 147, 164305). We find a broad feature in the experimental TCS at around 1.0 eV, which has been related to the formation of the NO2− anion and assigned to the π*(b1) resonance, according to previous mass spectra available in the literature. Other local maxima in the TCSs are found at 4.0 ± 0.2 and 5.0 ± 0.2 eV and are assigned to core excited resonances leading to the formation of the NO2− and O2− anions, respectively. Finally, for energies below 10 eV, differences found between the present measurements, the SMCPP calculation and our previous data for non-polar benzene have revealed the importance of accurately calculating the rotational excitation contribution to the TCS before comparing theoretical and experimental data. This comparison suggests that our dipole-Born calculation for nitrobenzene overestimates the magnitude of the rotational excitation Cross Sections below 10 eV.
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ab initio electron Scattering Cross Sections and transport in liquid xenon
Journal of Physics D, 2016Co-Authors: Gregory J Boyle, Stephen Buckman, M J Brunger, R P Mceachran, Daniel Cocks, S Dujko, R D WhiteAbstract:Ab initio fully differential Cross-Sections for electron Scattering in liquid xenon are developed from a solution of the Dirac–Fock Scattering equations, using a recently developed framework (Boyle et al 2015 J. Chem. Phys. 142 154507) which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent Scattering effects. A multi-term solution of Boltzmann's equation accounting for the full anisotropic nature of the differential Cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10−4–1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase Cross-Sections, is presented to improve the liquid Cross-Sections, which was found to enhance the accuracy of the transport coefficient calculations.
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ab initio electron Scattering Cross Sections and transport in liquid xenon
arXiv: Atomic Physics, 2016Co-Authors: Gregory J Boyle, Stephen Buckman, M J Brunger, R P Mceachran, Daniel Cocks, S Dujko, R D WhiteAbstract:Ab-initio electron - liquid phase xenon fully differential Cross-Sections for electrons Scattering in liquid xenon are developed from a solution of the Dirac-Fock Scattering equations, using a recently developed framework [1] which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent Scattering effects. A multi-term solution of Boltzmann's equation accounting for the full anisotropic nature of the differential Cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10^{-4} to 1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase Cross-Sections, is presented to transform highly accurate gas-phase Cross-Sections to improve the liquid Cross-Sections, which was found to enhance the accuracy of the transport coefficient calculations.
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electron Scattering Cross Sections for collisions with tetrahydrofuran from 50 to 5000 ev
Physical Review A, 2009Co-Authors: Martina Fuss, Francisco J Blanco, Gustavo Garcia, A Munoz, J C Oller, P Limaovieira, M J Brunger, Diogo AlmeidaAbstract:de Educacion y Ciencia Plan Nacional de Fisica, This study has been partially supported by the following research projects and institutions: Ministerio Project No. FIS2006-00702, Consejo de Seguridad Nuclear CSN, European Science Foundation COST Action CM0601 and EIPAM Project, Acciones Integradas Hispano-Portuguesas Project No. HP2006-0042
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electron molecule Scattering Cross Sections i experimental techniques and data for diatomic molecules
Physics Reports, 2002Co-Authors: M J Brunger, Stephen BuckmanAbstract:Abstract Experimental collision Cross-Sections for electron-molecule Scattering processes at low to intermediate energies (meV– 100 eV ) are compiled and critically reviewed. Recent advances in experimental techniques are summarised. Of principle interest are differential, total and momentum transfer Cross-Sections for elastic Scattering and rotational, vibrational and electronic excitation processes. Wherever possible, available theoretical Cross-Sections are also compared and discussed. Resonance effects, whilst not treated explicitly, are discussed in the context of the enhancement they produce in the various Scattering Cross-Sections. Scattering from excited molecules is also considered.
J C Oller - One of the best experts on this subject based on the ideXlab platform.
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electron Scattering Cross Sections from nitrobenzene in the energy range 0 4 1000 ev the role of dipole interactions in measurements and calculations
Physical Chemistry Chemical Physics, 2020Co-Authors: L Alvarez, A I Lozano, A Munoz, J C Oller, P Limaovieira, F M S Costa, Francisco Garcia Blanco, R D White, M J BrungerAbstract:Absolute total electron Scattering Cross Sections (TCS) for nitrobenzene molecules with impact energies from 0.4 to 1000 eV have been measured by means of two different electron-transmission experimental arrangements. For the lower energies (0.4–250 eV) a magnetically confined electron beam system has been used, while for energies above 100 eV a linear beam transmission technique with high angular resolution allowed accurate measurements up to 1000 eV impact energy. In both cases random uncertainties were maintained below 5–8%. Systematic errors arising from the angular and energy resolution limits of each apparatus are analysed in detail and quantified with the help of our theoretical calculations. Differential elastic and integral elastic, excitation and ionisation as well as momentum transfer Cross Sections have been calculated, for the whole energy range considered here, by using an independent atom model in combination with the screening corrected additivity rule method including interference effects (IAM-SCARI). Due to the significant permanent dipole moment of nitrobenzene, additional differential and integral rotational excitation Cross Sections have been calculated in the framework of the Born approximation. If we ignore the rotational excitations, our calculated total Cross section agrees well with our experimental results for impact energies above 15 eV. Additionally, they overlap at 10 eV with the low energy Schwinger Multichannel method with Pseudo Potentials (SMCPP) calculation available in the literature (L. S. Maioli and M. H. F. Bettega, J. Chem. Phys., 2017, 147, 164305). We find a broad feature in the experimental TCS at around 1.0 eV, which has been related to the formation of the NO2− anion and assigned to the π*(b1) resonance, according to previous mass spectra available in the literature. Other local maxima in the TCSs are found at 4.0 ± 0.2 and 5.0 ± 0.2 eV and are assigned to core excited resonances leading to the formation of the NO2− and O2− anions, respectively. Finally, for energies below 10 eV, differences found between the present measurements, the SMCPP calculation and our previous data for non-polar benzene have revealed the importance of accurately calculating the rotational excitation contribution to the TCS before comparing theoretical and experimental data. This comparison suggests that our dipole-Born calculation for nitrobenzene overestimates the magnitude of the rotational excitation Cross Sections below 10 eV.
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total electron Scattering Cross Sections from para benzoquinone in the energy range 1 200 ev
Physical Chemistry Chemical Physics, 2018Co-Authors: A I Lozano, J C Oller, P Limaovieira, D B Jones, R F Da Costa, M Do T N Varella, M H F Bettega, Ferreira F Da Silva, Marco A P LimaAbstract:Total electron Scattering Cross Sections, from para-benzoquinone, for impact energies ranging between 1 to 200 eV, have been obtained by measuring the attenuation of a linear electron beam under magnetic confinement conditions. Random uncertainty limits on these values have been found to be within 5%. Systematic errors, due to the axial magnetic beam conditions in combination with the acceptance angle of the detector, have been evaluated by integrating our calculated independent atom model with the screening corrected additivity rule and interference term elastic differential Cross Sections over that detection acceptance angle. Our previous calculations and measurements on this molecule (Jones et al., J. Chem. Phys., 2018, 148, 124312 and J. Chem. Phys., 2018, 148, 204305), have been compiled and complemented with new elastic and inelastic Scattering Cross section calculations in order to obtain a comprehensive Cross section data base, within the considered energy range, for modelling purposes. The self-consistency of the present data set has been evaluated by simulating the electron transport of 15 eV electrons in para-benzoquinone, and comparing those results with the observed transmitted intensity distribution.
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electron Scattering Cross Sections for collisions with tetrahydrofuran from 50 to 5000 ev
Physical Review A, 2009Co-Authors: Martina Fuss, Francisco J Blanco, Gustavo Garcia, A Munoz, J C Oller, P Limaovieira, M J Brunger, Diogo AlmeidaAbstract:de Educacion y Ciencia Plan Nacional de Fisica, This study has been partially supported by the following research projects and institutions: Ministerio Project No. FIS2006-00702, Consejo de Seguridad Nuclear CSN, European Science Foundation COST Action CM0601 and EIPAM Project, Acciones Integradas Hispano-Portuguesas Project No. HP2006-0042
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electron Scattering Cross Sections and stopping powers in h2
Physical Review A, 2007Co-Authors: A Munoz, Francisco J Blanco, J D Gorfinkiel, J C Oller, P Limaovieira, Gustavo GarciaAbstract:Total electron-H2 Scattering Cross Sections have been measured from 50 to 5000 eV with experimental errors of about 5%. Integral elastic and inelastic Cross Sections have been calculated with different methods, according to the incident electron energies. For energies up to 40 eV an R-matrix procedure has been used, while for intermediate and high energies (10–10 000 eV) an optical potential method has been applied by assuming an independent atom representation. From a detailed evaluation of the present results and their comparison with previous theoretical and experimental data, a complete set of recommended Cross sectional data (elastic, inelastic and total) is provided. By combining the integral Cross Sections with an average excitation energy derived from the experimental energy loss spectra the stopping power of electrons in H2 has been obtained from 5 to 5000 eV.
