Optical and dielectric properties of metallic calcium, modeled generalized oscillator strength function of calcium, interaction cross sections of electrons, protons, and alpha particles with calcium.

摘要

An analysis of the optical and the dielectric properties of calcium, determined from the literature, was performed. The optical functions of calcium were used for a calculation of the energy loss function of calcium. The energy loss function of calcium was used for a calculation of the oscillator strengths of electrons from the shells of calcium atoms and the bands of metallic calcium. The function was also used for a calculation of the mean excitation energies of electrons from the shells and the bands of calcium. The mean excitation energy of electrons from the whole atoms of calcium was found equal to 172 eV. The oscillator strengths and the partial mean excitation energies were used for modeling the generalized oscillator strength (GOS) function of calcium. The GOS function of calcium was first constructed with the Dirac's delta functions, and later with Gaussian functions adjusted for small and for large energy losses. The GOS function of calcium was used for a calculation of the energy loss and recoil energy differential interaction cross sections of charged particles with calcium. Calculations of the cross sections were performed for electrons, protons, and alpha particles. It was also shown that interaction cross sections of charged particles heavier then protons and fully stripped from electrons can be calculated from proton interaction cross sections by charge, mass, and speed scaling. The energy loss differential interaction cross sections were calculated by integration of the double differential interaction cross sections by the recoil energy. The inverse mean free path, the stopping power, and the energy straggling of electrons, protons, and alpha particles in calcium were also calculated. Calculated interaction cross sections can be used in computer simulations of a passage of energetic charged particles through media containing calcium. Such computer simulations can help for an assessment of the radiation damage induced by energetic charged particles to media in question.