Computational spectroscopy of atoms and applications to the fundamental problems‏

Abstract

Computations of the spectroscopic properties of several heavy atoms have been performed to establish a link between recent measurements and some problems in modern physics. Calculations for No and Fm atoms demonstrated that isotope shift measurements can be used to study nuclear structure by extracting nuclear parameters beyond the root mean square (RMS) radius, such as the quadrupole deformation. Calculations of isotope shift in Yb+ ion indicated that observed non-linearities of the King plot can be explained by nuclear deformation. This is a major systematic effect in the search for new interactions. Calculation of hyperfine structure (HFS) for heavy and superheavy elements provides a possibility to extract from future HFS measurements magnetic dipole and electric quadrupole moments of the nuclei. We carried out calculations of the magnetic dipole HFS constant (A) and electric quadrupole HFS constant (B) for the superheavy elements Fm and Rf and the heavy elements Cf and Es. Similar calculations have also been performed on the lighter homologs Er, Hf, Dy, and Ho, whose electronic structures are similar to Fm, Rf, Cf, and Es, respectively, to verify the calculations. We studied many excited metastable states in many heavy atoms and ions and found promising systems which can be used as very accurate atomic clocks which are highly sensitive to new physics. A number of atomic properties, such as energy levels, transition amplitudes, lifetimes, polarizabilities of the ground and clock states, etc., have been calculated. We found that relative blackbody radiation (BBR) shifts are small, between 10^−16 and 10^−18, and the effects of variation of the fine-structure constant (α) are enhanced up to 8.3 times. Calculations of atomic systems have been done using two different approaches. The choice depends on the number of valence electrons. The first method is called CI+SD (configuration interaction with single-double coupled cluster method), which is applicable to atomic systems with a few valence electrons (up to four). The second method is called CIPT (configuration interaction with perturbation theory method). It is designed to work with atomic systems with many valence electrons (more than four).