Off-energy two-body t-matrix in the R-matrix theory

Suggested is the generalization of R-matrix formalism permitting to describe off-energy behaViour of t-matrix in open two-body channels. It is shown that for complete determination of the off-energy t-matrix it is necessary to set not ouly energy levels and reduced widths of eigen-states but also additional parameters such as overlapping widths. Overlapping widths are expressed by the overlapping integrals in the region of interaction of wave functions of eigen-states and an incident wave. In the simplest case of the only open two-body channel obtained is a general expression for t-matrix the off-energy surface. Considered are limiting transitions to particular cases: two-body interaction with zero-range action, a model of a hard repulsing core, a square-well potential model