  A multi-channel scattering problem is studied from a point of view of
integral equations system. The system appears while natural one-particle wave
function equation of the electron under action of a potential with
non-intersecting ranges is considered.
  Spherical functions basis expansion of the potentials introduces partial
amplitudes and corresponding radial functions. The approach is generalized to
multi-channel case by a matrix formulation in which a state vector component is
associated with a scattering channel.
  The zero-range potentials naturally enter the scheme when the class of
operators of multiplication is widen to distributions. %Analog of multipolar
expansion is treated. Spin variables, o Oscillations and rotations are
incorporated into the scheme.
