XXVI International Conference on Photonic, Electronic and Atomic Collisions IOP Publishing Journal of Physics: Conference Series 194 (2009) 042038 doi:10.1088/1742-6596/194/4/042038
Calculations on various total cross-sections of electron impact on group VA – Atoms-Threshold to 2000 eV 1
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K. N. Joshipura, 2Sumona Gangopadhyay, 3Harshit N Kothari and 4Foram A Shelat
1, 2,3 Department of Physics, Sardar Patel University, Vallabh Vidyanagar – 388 120, INDIA GCET Engineering college, Sardar Patel University, Vallabh Vidyanagar – 388 120, INDIA
Synopsis In this paper we have calculated various total cross-sections of Nitrogen, Phosphorus, Arsenic, Antimony and Bismuth (Group VA-atoms) in the energy range of 15 to 2000 eV. Spherical Complex potential formalism is used to derive total as well as inelastic cross-sections. We have developed CSP-ic method by which we can extract ionization cress-section from the inelastic cross-section. Our results are compared with available theoretical and experimental data.
Among the group VA elements, nitrogen is an abundant and well – known atmospheric atom, and very few experimental data are available for comparison. In the present paper, we have calculated all various total cross sections for nitrogen and phosphorous, arsenic, antimony and bismuth for which the only available experimental results are by Freund et al [1]. Theoretical ionization cross sections are calculated by Santos and Parente [2], who made specific assumptions about the abundance of metastables as against the ground state species. We have employed the well-known spherical complex (optical) potential formalism [3] (SCOP), which provides total elastic cross-section Qel and its inelastic counterpart Qinel which includes Qion. We have employed a method to extract ionization cross sections Qion from calculated inelastic cross-section Qinel, by introducing a ratio function [4, 5]. ___________________________________ 1 2
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Here we have shown all cross-sections of Nitrogen atom of our present result along with all comparison of ionization cross-section which are available. Detailed results will be presented and discussed in the conference.
Present QT Qel Qinel Qexc Qion Present Kim Brook (2 keV) Brook (4 keV) N2/2 of Itikawa
e-N
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Total cross-sections (Å2)
Electron – impact ionization is one of the most fundamental collision processes in atomic and molecular physics. There is a need for reliable theoretical methods to calculate electron impact cross sections for large number of neutral atoms, occurring in a wide range of scientific and industrial applications, like, astrophysics, atmospheric science, X-ray lasers, etc. In this paper we have focused on electron scattering from various atomic beams, for which measured data are available from only one group, Freund et al [1]. They [1] have mentioned about the presence of metastable, and high - n species in the target atomic beams. That is why the present investigation is of interest.
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Ei (eV)
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Fig.1 All Total cross-sections (in Å2) of electron impact on Nitrogen atom along with comparison.
References [1] Freund R S, Wetzel R C, Shul R J and Hayes T R 1990 Phys. Rev. A 41 3575 [2] Santos J P and Parente F 2008 Eur. Phys. J. D 47 339 [3] Joshipura K N, Gangopadhyay Sumona and Vaishnav Bhushit G 2007 J. Phys. B 40 199 [4] Joshipura K N, Vaishnav Bhushit G and Gangopadhyay Sumona 2007 Int. J. Mass. Spectrom 261 146 [5] Joshipura K N, Vaishnav B G and Limbachiya C G 2006 Pramana J. Phys 66 403
