T-matrix method and singularities of analytical continuation of wave field

The reason of limitations on scatterer geometry imposed by T-matrix method is ascertained. The condition of correctness of T-matrix method application is given. It is shown that at numerical solution of integral equations on the basis of null field condition, in particular at using T-matrix method it is necessary to take into account singularities of analytical continuation of wave field. Theoretical results are illustrated by numerical examples.