Cross section of photoabsorption on Thomas-Fermi atom

The photoabsorption cross section σ(ω) and the oscillator forces distribution df/dω are obtained for the atom with large Z on the basis of the quasi-classical approach. These values for the low frequencies are determined by the Vlasov kinetic equations, which are numerically solved through the particles method. The asymptotics of the oscillators forces distribution at high frequencies is obtained through the quasiclassical formulae for the photoabsorption cross sections on the electron shells in the Coulomb potential. The interpolation formula for the oscillators forces distribution within the whole Thomas-Fermi frequency range of 27 eV<<hω<<27 Z2 eV is proposed on the obtained asymptotics. The logarithmic average excitation energy, appearing in the tasks on the charged particles ionization losses, is calculates by means of this formula