Electron-impact excitation cross sections for Ar and Ar + by unitarized distorted-wave approximation

Unitarization for a relativistic distorted-wave approximation has been made by using two types of scattering matrix for reactance matrix and the electron-impact excitation cross sections for Ar and Ar${}^{+}$ are calculated by the unitarized relativistic distorted-wave method. The unitarization by using the scattering matrix obtained from diagonalization of the reactance matrix significantly reduces the cross sections rather than by using the scattering matrix given from inversion of matrix related to the reactance matrix which brings out better agreement with other more sophisticated R-matrix prediction and experiments at intermediate electron energies for Ar. The cross sections for Ar${}^{+}$ by the effective unitarization are smaller than those by available other prediction using perturbative relativistic distorted-wave approach.