  In this work we outline a general method for calculating Auger spectra in
molecules, which accounts for the underlying symmetry of the system. This
theory starts from Fano's formulation of the interaction between discrete and
continuum states and generalizes this formalism to deal with the simultaneous
presence of several intermediate quasi-bound states and several non-interacting
decay channels. Our theoretical description is specifically tailored to
resonant autoionization and Auger processes, and includes explicitly the
incoming wave boundary conditions for the continuum states and an accurate
treatment of the Coulomb repulsion. This approach is implemented and applied to
the calculation of the $K-LL$ Auger and autoionization spectra of ozone, which
is a $C_{2v}$ symmetric molecule, whose importance in our atmosphere to filter
out radiation has been widely confirmed. We also show the effect that the
molecular point group, and in particular the localization of the core-hole in
the oxygen atoms related by symmetry operations, has on the electronic
structure of the Auger states and on the spectral lineshape by comparing our
results with experimental data.
