  X-ray spectra from cores of galaxy clusters can be strongly distorted by
resonant scattering of line photons, affecting metal abundance and gas velocity
measurements. We introduce simulated spectral models that take into account the
resonant scattering effect, radial variations of thermodynamic properties of
the hot gas, projection effects and small-scale isotropic gas motions. The key
feature of the models is that all these effects are treated self-consistently
for the whole spectrum, rather than for individual lines. The model spectra are
publicly available and can be used for direct comparison with observed
projected spectra. Comparison with the existing XMM-Newton and Chandra data of
the Perseus Cluster shows that even though there is no strong evidence for the
resonant scattering in Perseus, the low energy resolution of the X-ray CCDs is
not sufficient to robustly distinguish spectral distortions due to the resonant
scattering, different metal abundance profiles and different levels of gas
turbulence. Future Astro-H data will resolve most of the problems we are facing
with CCDs. With the help of our models, the resonant scattering analysis can be
done self-consistently using the whole spectral information, constraining the
level of gas turbulence already with a 100 ks observation with Astro-H.
