  The vibrational excitations of ozone, including both bending and stretching
vibrations, are studied in the framework of a symmetry-adapted algebraic
approach. This method is based on the isomorphism between the U(2) algebra and
the one-dimensional Morse oscillator, and the introduction of point group
symmetry techniques. The use of symmetry-adapted interactions, which in the
harmonic limit have a clear physical interpretation, makes it possible to
systematically include higher order terms and anharmonicities. A least-square
fit to all published experimental levels (up to ten quanta) of 16 O_3 and 18
O_3 yields a r.m.s. deviation of 2.5 and 1.0 1/cm, respectively.
