MEAN-SQUARE RADII AND QUADRUPOLE-MOMENTS OF EVEN-EVEN ISOTOPES WITH 38 LESS-THAN-OR-EQUAL-TO Z LESS-THAN-OR-EQUAL-TO 60, N LESS-THAN-OR-EQUAL-TO 74

The sizes and shapes of the even-even Sr-Nd isotopes with mass number A approximately 100 are calculated microscopically. The quadrupole and hexadecapole deformations are taken as the collective variables. The single-particle Nilsson potential is used. The collective hamiltonian was obtained from a generator-coordinate method using the gaussian overlap approximation. The expectation values of the square radii and the mean quadrupole moments between the groundstate collective wave function are compared with the experimental data. It is found that one has to omit the isotopic dependence in the frequency homega0BAR of the Nilsson potential for protons in order to reproduce the isotopic shifts of the mean-square-charge radii.