Electron excitation and autoionisation cross sections for elements of chemically peculiar stars: Study of bismuth

27th Summer School and International Symposium on the Physics of Ionized Gases

Predojevi, B.^1,2 ; Pejev, V.^1 ; Evi, D.^1 ; Marinkovi, B.P.^1

Institute of Physics, University of Belgrade, POB 68, 11080, Serbia^1

Faculty of Natural Sciences, University of Banja Luka, Bosnia and Herzegovina^2

关键词: Chemically peculiar;    Chemically peculiar-stars;    Differential cross section;    Electron excitations;    Electron-impact excitation;    Energy-loss spectrum;    Incident electrons;    Scattered electrons;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/565/1/012019/pdf
DOI  :  10.1088/1742-6596/565/1/012019

来源: IOP

【 摘 要 】

Electron impact excitation from the ground state of bismuth atoms has been studied. A beam of electrons was scattered from a beam of atoms and the intensity of scattered electrons was measured for scattering angles up to 150°and incident electron energies of 40 and 60 eV. Obtained intensities were used for the calculation of relative differential cross sections (DCS). In addition, we recorded the energy loss-spectra at different incident electron energies and scattering angles. These spectra were analysed in order to identify the energy levels of bismuth atom below and above (autoionisation) the first ionization limit in electron spectroscopy. The presence of bismuth was confirmed in spectra of the chemically peculiar (CP) magnetic Ap 73 Dra and HR 465 and nonmagnetic Hg-Mn HR 7775 and χ Lupi stars. The obtained results for relative DCS and identified autoionised energy levels of bismuth were analysed and compared with previous experimental and theoretical data. The connection between our investigations of bismuth and astrophysical measurements are discussed.