Comments on ''Scattering with absorptive interactions''

In a recently published paper, Cassing and collaborators discussed the general tendencies of the motion of the complex poles of the S matrix of a complex potential with increasing absorption. In this Comment, it is pointed out that their conclusions are in fact model dependent and therefore are not valid for as wide a class of complex potentials as is suggested. Because of this model dependence of these conclusions, questions about the generalized Levinson's theorem proposed by these authors for complex interaction are raised