  The term rotational frequency shift (RFS) has been used in different contexts
and it was given different meanings. Other terms have also been used (azimuthal
Doppler shift, angular Doppler shift) to describe various related phenomena. In
this article we stick to the meaning of the rotational frequency shift given by
us in Phys. Rev. Lett.78, 2539 (1977). In order to make a clear distinction
between our RFS and other related shifts we use the term dynamical RFS (DRFS).
We will study the spectral properties of radiation emitted by rotating quantum
sources.
