Time- dependent exchange perturbation theory

A general formalism Time-dependent Exchange Perturbation Theory (TDEPT) is built. The formalism TDEPT is reduced to the standard form of invariant perturbation theory, taking into account the fundamental indistinguishability principle of electrons for polyatomic system. A scattering Smatrix and T-matrix transitions are obtained in a general form for arbitrary interactions. Applications of the theory to scattering and collision problems are discussed. A cross section of atomic scattering accounted interatomic electron permutation is developed in general form taking into account exchange inputs.