SEMI-CLASSICAL PERTURBATION EXPANSION OF THE MULTICHANNEL SCATTERING MATRIX

A semiclassical perturbation method for the inelastic S matrix is described. The channels are transformed into a set of the eigenstates and it is assumed that the transition between them is small. The perturbation is the matrix which diagonalizes the coupling matrix. It is shown that such a series is independent of h; hence the limit h →0 of the S matrix can be calculated. A special case of the weak coupling is also discussed. © 1979 American Institute of Physics.