In quantum chemistry, the state of a physical system is usually described by a wave function in the position space. However, it is also well known that a wave function in the momentum space can provide complementary information for electronic structure of atoms or molecules. The momentumspace wave function is especially useful to analyze the experimental results of scattering problems, such as Compton profiles and ( e, 2 e) measurements. In the present work, we focus on the innershell ionization processes of atoms by chargedparticle impact and study how the electron momentum distribution affects on the innershell ionization cross sections.
The momentum wave functions in various atomic models are calculated for arbitrary atomic orbitals. The nonrelativistic hydrogenic, the HartreeFock, the relativistic hydrogenic and the DiracFock models are considered. The momentum wave functions are obtained as a Fourier transform of the wave functions in the position space. The HartreeFock and the DiracFock wave functions in atoms are given in terms of Slatertype orbitals (STO's) and all the wave functions in the momentum space can be expressed analytically in terms of hypergeometric functions.
The momentum wave functions thus obtained are used to calculate innershell ionization cross sections by chargedparticle impact in the binaryencounter approximation (BEA). The wavefunction effect and the electronic relativistic effect on the innershell ionization processes are discussed.
