MJK: A program to calculate observable quantities in electron–atom collisions Original Research Article

We describe a code which utilizes partial-wave amplitudes to calculate a variety of physical quantities studied in electron–atom scattering. For elastic scattering and excitation of atoms with arbitrary angular momenta in collisions with spin-polarized and unpolarized electrons, the program can calculate angle-integrated and angle-differential cross sections, the spin polarization of scattered electrons, the spin left–right (up–down) asymmetry, generalized STU parameters, and the statistical tensors of the final atomic state, which determine polarization and correlation parameters in radiative and nonradiative decays of these states. In addition, the program transforms partial-wave scattering amplitudes into a representation of projections of the angular momenta in the natural and collision coordinate frames, thereby providing the possibility for a user to conveniently calculate any observable not explicitly included in the code. The program can be used directly as a final module after running the Belfast R-matrix codes in the Breit–Pauli mode.