Long-range and elementary contributions for quantum fluids at zero temperature

The effect of the optimal correlation function on the energy and momentum distribution is analyzed in 4He and normal 3He liquids. The interpolating integral equation is used for approximating the elementary contribution. The energies obtained in both cases are in good agreement with the results furnished by the scaling approximation. The value estimated for the 4He condensate fraction is close to that one calculated by PUOSKARI and KALLIO by using a mixture formalism, but differs to some extent from the prediction of the scaling technique. The inclusion of a long-range tail in the distribution function results to have a small effect on the normal 3He momentum distribution