Correlation operator method as an application of effective interaction theory

The unitary-model-operator approach (UMOA), a kind of the correlation operator method, is discussed in the framework of the general theory of effective interaction. The two-body effective interaction ṽ12, introduced as a basic element in the UMOA, has some desirable properties of being E-independent, Hermitian and decoupled between a model space and its complement. The UMOA is applied to the calculation of the ground-state properties in O and Ca with various nucleon-nucleon potentials. It is shown that the binding and single-particle energies, the one-body l-s splittings and the charge radii are reproduced fairly well in comparison with other calculations.