Rayleigh scattering from hydrogen atoms including resonances and high photon energies

The non-relativistic cross section from Rayleigh scattering by hydrogen atoms in the ground state is calculated over a wide range of photon energies ($< 0.8$ keV). Evaluations are performed terms real and imaginary components atomic polarizability. sum intermediate states that characterizes this second-order radiative process using exact analytic expressions for oscillator strengths bound continuum states. Damping associated with finite lifetimes excited their splitting into two fine-structure levels ($p_{1/2}$ $p_{3/2}$) taken account resonance sections. Fitting formulas required cross-section evaluation presented incident energy i) redward first (Lyman-$\alpha_{1/2}$), ii) spectral region corresponding to resonances (for an arbitrary number them), iii) above ionization threshold.