KOHN VARIATIONAL PRINCIPLE FOR A GENERAL FINITE-RANGE SCATTERING FUNCTIONAL

The Kohn variational principle (KVP) has been used to compute both the R and the log-derivative matrices, which are formally inverses of one another. We show that the KVP for these matrices are special cases of a KVP for a more general functional which can be derived by imposing more general boundary conditions on the trial function space. This mor e general matrix, which we denote Z, can then be used to compute the S -matrix in a procedure analogous to that for R and Y. This approach is demonstrated for the Eckart barrier problem. Our studies suggest that within the framework presented, the log derivative case presents some computational advantage.