  Method of evaluating chemical shifts of X-ray emission lines for sufficiently
heavy atoms (beginning from period 4 elements) in chemical compounds is
developed. This method is based on the pseudopotential model and one-center
restoration method (to reconstruct the proper electronic structure in
heavy-atom cores). The approximations of instantaneous transition and frozen
inner core spinors of the atom are used for derivation of an expression for
chemical shift as a difference between mean values of some effective operator.
The method allows one to avoid evaluating small values (chemical shifts ~$
0.01{-}1$ eV) as differences of very large values (transition energies ~
$1{-}100$ keV in various compounds). The results of our calculations of
chemical shifts for the $K\alpha_1$, $K\alpha_2$, and L transitions of the
group 14 metal cations with respect to neutral atoms are presented. The
calculations of chemical shift of $K\alpha_1$-line in the Pb-core transition
within PbO and PbF$_2$ with respect to the neutral Pb are also performed and
discussed. The accuracy of the used approximations is discussed and quality of
the performed calculations is analyzed.
