For all stable nuclei, x must be less than 1. In that case, the total deformation energy of nuclei undergoing fission will increase by an amount ( 1 / 5 ) α α 2 2 ( 2 E s 0 − − E c 0 ) , as the nucleus deforms towards fission. This increase in potential energy can be thought of as the activation energy barrier for the fission reaction. However, modern calculations of the potential energy of deformation for the liquid drop model involve many deformation coordinates aside from α α 2 and represent major computational tasks.