  The structure of the rate of variation of the atomic energy for an arbitrary
stationary motion of the atom in interaction with a quantum electromagnetic
field is investigated. Our main purpose is to rewrite the formalism in Ref.
\cite{zz} and to deduce the general expressions of the Einstein A coefficients
of an atom on an arbitrary stationary trajectory. The total rate of change of
the energy and Einstein coefficients of the atom near a plate with finite
temperature or acceleration are also investigated.
