Optically Forbidden Excitations of 3s Electron of Argon by Fast Electron Impact

The electron energy loss spectrum of argon in the energy region of 24.5—30.5 eV was measured at 2.5 ke V impact energy. The line profile parameters of the optically forbidden excitations of 3s^-1 ns (n = 4-6) and 3s^-1 nd (n = 3-7) of argon, i.e., Er,Г,q and μ were determined.     

Theoretical Study on Inner Shell Electron Impact Excitation of Lithium

Cross sections for electron impact excitation of lithium from the ground state 1s^22s to the excited states 1s2s^2, 1s2p^2, 1s2snp （n = 2-5）, 1s2sns （n = 3 5）, 1s2pns （n = 3-5）, and 1s2pnp （n = 3-5） are calculated by using a full relativistic distorted wave method. The latest experimental electron energy loss spectra for inner-shell electron excitations of lithium at a given incident electron energy of 2500 eV [Chin. Phys. Lett. 25 （2008）3649] have been reproduced by the present theoretical investigation excellently. At the same time, the structures of electron energy loss spectra of lithium at low incident electron energy are also predicted theoretically, it is found that the electron energy loss spectra in the energy region of 55-57eV show two-peak structures.