  The dynamical evolution of self-gravitating scalar field configurations in
numerical relativity is studied. The previous analysis on ground state boson
stars of non-interacting fields is extended to excited states and to fields
with self couplings.
  Self couplings can significantly change the physical dimensions of boson
stars, making them much more astrophysically interesting (e.g., having mass of
order 0.1 solar mass). The stable ($S$) and unstable ($U$) branches of
equilibrium configurations of boson stars of self-interacting fields are
studied; their behavior under perturbations and their quasi-normal oscillation
frequencies are determined and compared to the non-interacting case.
  Excited states of boson stars with and without self-couplings are studied and
compared. Excited states also have equilibrium configurations with $S$ and $U$
branch structures; both branches are intrinsically unstable under a generic
perturbation but have very different instability time scales. We carried out a
detailed study of the instability time scales of these configurations. It is
found that highly excited states spontaneously decay through a cascade of
intermediate states similar to atomic transitions.
