Coulomb energy contribution to the excitation energy in 229Th and enhanced effect of α variation

We estimated the polarization contribution of Coulomb energy to the spacing between the ground and first excited state of the Th-229 nucleus as a function of the deformation parameter delta. We show that despite the fact that the odd particle is a neutron, the change in Coulomb energy Delta U-C between these two states can reach several hundreds keV from this contribution. This means that the effect of the variation of the fine-structure constant alpha = e(2)/hc may be enhanced Delta U-C/E similar to 10(4) times in the E = 7.6 eV "nuclear clock" transition between the ground and first excited states in the Th-229 nucleus. To extract the full value of Delta U-C, we propose to measure isomeric shift of atomic levels and nuclear electric quadrupole moments in Th-229. Copyright (C) EPLA, 2009