Enhancement of nuclear Schiff moments and time reversal violation in atoms due to combination of soft nuclear octupole and quadrupole vibrations

Nuclear forces violating parity and time reversal invariance P,T-odd produce P,T-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce the electric dipole moment (EDM) in the atom. The contribution to the Schiff moment from the soft collective quadrupole and octupole vibrations in spherical nuclei is calculated in the framework of the quasiparticle random phase approximation with separable quadrupole and octupole forces. The values of nuclear Schiff moments predicted for odd 217-221Ra and 217-221Ra isotopes indicate a possibility of enhancement by a factor of 50 or more as compared to the experimentally studied spherical nuclei 199Hg and 129Xe. Since the EDM in very heavy atoms, such as Ra, Rn, and Fr, has an additional enhancement rapidly increasing with nuclear charge $Z$, the EDM enhancement can exceed two orders of magnitude. We discuss the nuclear structure effects causing an enhancement of the Schiff moment.