  Pair Instability Supernovae have been suggested as candidates for some Super
Luminous Supernovae, such as SN 2007bi, and as one of the dominant types of
explosion occurring in the early Universe from massive, zero-metallicity
Population III stars. The progenitors of such events can be rapidly rotating,
therefore exhibiting different evolutionary properties due to the effects of
rotationally-induced mixing and mass-loss. Proper identification of such events
requires rigorous radiation hydrodynamics and radiative transfer calculations
that capture not only the behavior of the light curve but also the spectral
evolution of these events. We present radiation hydrodynamics and radiation
transport calculations for 90-300 Msun rotating pair-instability supernovae
covering both the shock break-out and late light curve phases. We also
investigate cases of different initial metallicity and rotation rate to
determine the impact of these parameters on the detailed spectral
characteristics of these events. In agreement with recent results on
non-rotating pair instability supernovae, we find that for a range of
progenitor masses and rotation rates these events have intrinsically red colors
in contradiction with observations of super-luminous supernovae. The
spectroscopic properties of rotating pair instability supernovae are similar to
those of non-rotating events with stripped hydrogen and helium envelopes. We
find that the progenitor metallicity and rotation rate properties are erased
after the explosion and cannot be identified in the resulting model spectra. It
is the combined effects of pre-supernova mass-loss and the basic properties of
the supernova ejecta such as mass, temperature and velocity that have the most
direct impact in the model spectra of pair instability supernovae.
