The distributions of the momenta of the two electrons liberated in nonseque
ntial double ionization of neon and argon are calculated in the S-matrix fo
rmalism assuming a rescattering scenario. Two different forms for the elect
ron-electron correlation are compared: the Coulomb repulsion in the Born ap
proximation and a three-body contact interaction including the ion. The for
mer favors disparate momenta of the two electrons, the latter equal momenta
.