The fission of highly charged sodium clusters with fissilities X > 1 is stu
died by ab initio molecular dynamics. Na-24(4+) is found to undergo predomi
nantly sequential Na-3(+) emission on a time scale of 1 ps, while Na-24(Q+)
(5 less than or equal to Q less than or equal to 8) undergoes multifragmen
tation on a time scale greater than or equal to0.1 ps, with Na+ increasingl
y the dominant fragment as Q increases. All singly charged fragments Na-n() up to size n = 6 are observed. The observed fragment spectrum is, within
statistical error, independent of the temperature T of the parent cluster f
or T less than or equal to 1500 K. These findings are consistent with and e
xplain recent trends observed experimentally.