OPTIMIZED PERTURBATION THEORY TO CALCULATING THE HYPERFINE LINE SHIFT AND BROADENING FOR HEAVY ATOMS IN THE BUFFER GAS
It is presented review of a new consistent relativistic approach to determination of collisional shift and broadening hyperne lines for heavy atoms in an atmosphere of the buffer inert gas. It is based on the atomic gauge-invariant relativistic perturbation theory and the exchange perturbation theory. As illustration, consistent approach is applied to calculating the interatomic potentials, hyperne structure line collision shift and broadening for heavy atoms, in particular, atoms of alkali elements - rubidium, caesium, and thallium, ytterbium, in an atmosphere of the buffer inert gas