For certain combinations of protons and neutrons in atomic nuclei, a rise of a reflection asymmetry is expected. Experimental E3 strengths, which as a function of the neutron number peak at around N approximate to 8 8 and N approximate to 1 3 4, indicate enhanced octupole correlations as predicted by theory. Low-energy Coulomb excitation is a highly successful method for establishing the evolution of nuclear shapes, through the measurement of cross sections, to populate excited states that can be directly related to the static and dynamic moments of the charge distribution of the nucleus. A Coulomb excitation experiment at the ALTO facility, Orsay was performed recently to study collective properties of Nd-146 and Sm-148. In particular, the strengths of the and matrix elements will provide a clear distinction between octupole vibration and rigid deformation.