Electric Quadrupole Moments of Light and Heavy Nuclei

Under the assumption that the asymmetrical nuclear charge distribution is due to a single proton, a general expression for the electric quadrupole moment as a function of nuclear spin is obtained. Using the plausible restriction for heavy nuclei that all allowed pairs of values of the orbital angular momentum of the proton and of the core occur with equal probability, we get as a result that the quadrupole moment is negative and that the value increases negatively as the nuclear spin increases. The calculation for light nuclei, taking into account the effect of all particles by using the Hartree model, shows that the addition of a proton to a nucleus, whose $Q$ was originally zero, produces a negative quadrupole moment.