WebThe cross sections for photoionization from the 2 S 1, 2 S 3, 2 P 1, and 2 P 3 excited states of helium are calculated for photoelectron energies below the n = 2 threshold of … WebDouble photoionization of helium by a single photon has been studied for a period of more than 40 years since the pioneering work of Byron and Joachain Byron and Joachain (), who pointed out the importance of electron correlation in the process.Such correlated processes pose many challenges, and it is only during the last 15 years or so that quantitative …

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WebThe photoionization cross sections of helium have been measured from threshold down to 260 Å. At the spectral head the cross section is found to be 7.3×10−18 cm2. The … Webment with theoretical calculations on helium is demonstrated to be within ± 2-3 % from threshold down to the double ionization threshold at 79 eV. Comparison with recent … The photoemission is a useful experimental method for the determination and the study of the electronic states. Sometimes the small amount of deposited material over a surface has a weak contribution to the photoemission spectra, which makes its identification very difficult. The knowledge of the cross section of a material can help to detect thin layers or 1D nanowires over a substrate. A right choice of the photon energy can enhance a small amount of material deposite… iss cotia login