Separable expansion of the t-matrix in the 3S1-3D1 channel

A recently proposed separable expansion for the t-matrix for local potentials is extended to the coupled channel of nucleon-nucleon interactions. The simple method yields a rather convergent separable expansion, with simple form factors, and the requirements of two particle unitarity and time reversal symmetry are maintained for approximations of any rank. The method is illustrated for the simplified Reid soft-core potential in the ³S₁-³D₁ channel, and the results compared with a recent calculation of Pieper.