The exponential distorted-wave approach for systems for which the S matrix of the distorted wave is not diagonal
Michael Sisak, Don Secrest · The Journal of Chemical Physics · 1992
The recoupled states approximation is a distorted-wave approximation and as such leads to a nonunitary S matrix. Several unitarization approaches are known for systems for which the S matrix of the distorted wave is diagonal. In particular, the exponential distorted-wave method has been extremely successful. We develop in this paper a general unitarization technique, similar to the exponential distorted-wave method, useful when the S matrix of the distorted wave is nondiagonal. This approach is applied to the case of the recoupled states for which the distorted waves are the coupled states wave functions. For this particular example, unitarization does not improve the results.