Electron scattering cross sections from nitrobenzene in the energy range 0.4-1000 eV: the role of dipole interactions in measurements and calculations

Alvarez, L., Costa, F., Lozano, A., Oiler, J.C, Munoz, A., Blanco, F., Limao-Vieira, P., White, R.D., Brunger, M.J., and Garcia, G. (2020) 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, 22 (24). pp. 13505-13515.

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Abstract

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 NO(2)(-)anion and assigned to the pi*(b(1)) 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 NO(2)(-)and O(2)(-)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.

Item ID: 63798
Item Type: Article (Research - C1)
ISSN: 1463-9084
Keywords: Electrons, fatigue crack propagation, mass spectrometry, negative ions, nitrobenzene, nitrogen oxides, systematic errors, transmissions
Copyright Information: This journal is © the Owner Societies 2020. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.
Funders: Spanish Ministerio de Ciencia, Innovation y Universidades (SMC), Spanish National Research Council (CSIC), Radiation Biology and Biophysics (RBB), Applied Molecular Biosciences Unit (UCIBIO), Portuguese National Funding Agency (PNFA), Australian Research Council (ARC)
Projects and Grants: SMC Project FIS2016-80440, CSIC Project LINKA 20085, RBB Doctoral Training Programme RaBBiT, PD/00193/2012, UCIBIO Grant UIDB/04378/2020, PNFA Grant CEFITEC UIDB/00068/2020, PNFA Grant PTDC/FIS-AQM/31281/2017, ARC DP160102787, ARC DP180101655, CSIC Open Access Publication Support Initiative
Date Deposited: 15 Jul 2020 07:56
FoR Codes: 51 PHYSICAL SCIENCES > 5106 Nuclear and plasma physics > 510602 Plasma physics; fusion plasmas; electrical discharges @ 100%
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