MODEL-CALCULATIONS OF DOUBLY CLOSED-SHELL NUCLEI IN THE INTEGRODIFFERENTIAL EQUATION APPROACH

The binding energies and root mean square radii obtained from the Inte gro-Differential Equation Approach (IDEA) and from the Weight-Function Approximation (WFA) of the IDEA for an even number of bosons and for C-12, O-16 and Ca-40 are compared to those recently obtained by the Va riational Monte Carlo, Fermi Hypernetted Chain and Coupled Cluster exp ansion methods with model potentials. The IDEA provides numbers very s imilar to those obtained by other methods although it takes only two-b ody correlations into account. The analytical expression of the wave f unction for the WFA is given for bosons in the ground state when the i nteracting pair is outside the potential range. Due to its simple stru cture, the equations of the IDEA can easily be extended to realistic i nteractions for nuclei as has already been done for the trinucleon and He-4.