Theory and applications of atomic and ionic polarizabilities

Abstract

Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wave functions, interferometry with atom beams, and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards.

When should we change the definition of the second?

“…171 Yb + octupole) quadrupole shift has attraction. In parallel, the room-temperature blackbody shifts for 27 Al + , 115 In + and 171 Yb + octupole clock transitions are −0.04, −0.14 and −1.6 × 10 −16 , respectively [65,66]. For the atom clock species, the blackbody shifts are 16× and 34× higher for 171 Yb and 87 Sr than for the 171 Yb + octupole transition, respectively.…”

“…For the atom clock species, the blackbody shifts are 16× and 34× higher for 171 Yb and 87 Sr than for the 171 Yb + octupole transition, respectively. Of the atoms, only 199 Hg has a low blackbody shift (−1.6 × 10 −16 ) [65,66] on account of its UV frequency. Generically, the oddisotope atom systems have linear Zeeman shifts some three orders of magnitude lower than the corresponding ions, and the ion clocks will generally require magnetic shielding.…”

Effect of the atomic electric quadrupole moment on positron binding

“…In some excited atomic states the polarizability may be very small or even negative [23]. Therefore, it is interesting to check if the quadrupole alone (for α = 0) may provide the positron binding.…”

Two-photonE1-M1optical clock

“…The estimated black-body radiation shifts and uncertainties have been cataloged elsewhere [29]. At 380 K the shift is −1.63 Hz.…”