Multipolarity effects in ionization of the inner level of an atom by an electron impact in extended fine structures of K and L spectra of electron energy losses

The problem of multipolarity of the atom core level ionization by electron impact in extended energy loss fine structure (EELFS) spectroscopy is studied. The intensities and amplitudes of electron transitions have been calculated in the OPW approximation. The experimental K EELFS spectra of Al, Si and L EELFS spectra of Fe, Co have been obtained. Corresponding calculations have been carried out in the monopole and dipole approximations. A comparison of theoretical and experimental spectra have been made. It is shown that a good agreement between the theoretical and experimental results points to the need for taking account of multipolarity of the electron transition processes in EELFS calculations.