Scattering of charged particles by atoms

A closed variant of the Born approximation for calculating differential sca ttering cross sections in ion-atom collisions is developed. An expression i n terms of the matrix elements J(ij) with respect to the single-electron st ates of the atom is found for the matrix element describing the target atom in the formula for the differential cross section. The matrix elements J(i j) are averaged over the relative orientation of the momentum transferred i n the collision and the symmetry axis of the electronic orbitals of the tar get atom, using the single-electron Rutaan-Hartree-Fock wave functions. The algebraic representation of the matrix elements J(ij) makes it possible to perform calculations for atoms with any value of Z. The model developed is used to calculate the cross sections sigma (Sigma) and characteristic scat tering angles theta (c) for the process of electron loss by H- ions with en ergy E = 0.1-100 MeV in targets consisting of atoms with Z = 2-54. It is sh own that sigma (Sigma) proportional to E (-1) and theta (c) proportional to E (-1/2) for all Z, and for fixed E the behavior of sigma (Sigma)(Z) and t heta (c)(Z) is determined by the order of filling of the electronic shells of the target atoms (the ionization potential). The computational results a re analyzed and compared with the experimental data and the results of othe r calculations. (C) 2000 MAIK "Nauka/Interperiodica".