  Atutov and Shalagin (1988) proposed light-induced drift (LID) as a physically
well understandable mechanism to explain the formation of isotopic anomalies
observed in CP stars. We generalized the theory of LID and applied it to
diffusion of heavy elements and their isotopes in quiescent atmospheres of CP
stars. Diffusional segregation of isotopes of chemical elements is described by
the equations of continuity and diffusion velocity. Computations of the
evolutionary sequences for abundances of mercury isotopes in several model
atmospheres have been made using the Fortran 90 program SMART, composed by the
authors. Results confirm predominant role of LID in separation of isotopes.
