Charge radii in macroscopic-microscopic mass models

We have calculated the charge radii in the framework of the finite-range droplet model (FRDM) for 884 nuclei for which experimental charge radii are available. By comparing the results with the experimental radii, we found that the calculated radii were too big on average. This deviation can be minimized if we assume a nonstandard small value for the a_den parameter in the FRDM calculation. However, even if we use this value, the calculated radii still deviate from the experimental ones in a systematic manner. Although we have calculated the shell corrections by using the microscopic wave function model and added them to the FRDM radii, the deviations have not been improved. (author)