We study a wide range of neutral atoms and ions suitable for ultra-precise atomic optical clocks with naturally suppressed black body radiation shift of clock transition frequency. Calculations show that scalar polarizabilities of clock states cancel
each other for at least one order of magnitude for considered systems. Results for calculations of frequencies, quadrupole moments of the states, clock transition amplitudes and natural widths of upper clock states are presented.
We discuss possible search for optical transitions in Sm13+ and Sm14+ using ab initio calculations of differential dynamic polarizability. We calculate dynamic polarizability for M1 transition between first and second excited states of Sm14+ . Transi
tion amplitudes and energies within optical range for states that contribute to the polarizability of the mentioned transition are presented. Employing simple analytical formula for polarizability data in the vicinity of a resonance and assuming that several values of the polarizability for different laser frequencies will be measured one can find the accurate position of the resonance. Results of similar calculations of amplitudes and energies of states that contribute to the polarizability of the M1 transition between ground and first excited states of Sm13+ are also presented.
The possibility of using neutral and double ionized erbium for atomic clocks of high precision is investigated. In both cases the narrow electric quadrupole clock transition between the ground and first exited state of the same configuration lies in
optical region. The estimated ratio of decay width to transition energy is less then 10 20. We demonstrate that this transitions are not sensitive to black body radiation and if other perturbations are also considered the relative accuracy of the clocks can probably reach the level of 10 (pow minus 18) or better.
