  We study the effect of quantum interference on the structure and properties
of spontaneous and stimulated transitions in a degenerate V-type three-level
atom with an arbitrary total momentum of each state. Explicit expressions for
the factors in the terms of the relaxation operator and stimulated transition
operator with account of quantum interference effects are obtained. It has been
demonstrated that the condition for the dipole transition moments to be
parallel is insufficient and for conventional atoms the interference cross
terms are zeros for both operators. The conditions when quantum interference
influences the properties of the relaxation operators have been analysed. For
the stimulated transitions this condition is shown to be anisotropy of the
photon field interacting with the atoms. This case is minutely studied for the
D-line of alkali metals.
