Iterative techniques of the solution of the decoupling equation are used to construct various types of effective Hamiltonians in the framework of nonorthogonal transformations. A general and numerically convenient Hermitization procedure of the non-Hermitian Hamiltonians obtained by such techniques is proposed and the definition of effective operators with the related normalization problems is reviewed. © 1996 The American Physical Society.

• Received 1 March 1996

DOI:https://doi.org/10.1103/PhysRevC.54.684