  We study the $z=0$ properties of clusters (and large groups) of galaxies
within the context of interacting and non-interacting quintessence cosmological
models, using a series of adiabatic SPH simulations. Initially, we examine the
average properties of groups and clusters, quantifying their differences in
LCDM, uncoupled Dark Energy (\ude) and coupled Dark Energy (\cde) cosmologies.
In particular, we focus upon radial profiles of the gas density, temperature
and pressure, and we also investigate how the standard hydrodynamic equilibrium
hypothesis holds in quintessence cosmologies. While we are able to confirm
previous results about the distribution of baryons, we also find that the main
discrepancy (with differences up to $20\%$) can be seen in cluster pressure
profiles. We then switch attention to individual structures, mapping each halo
in quintessence cosmology to its \LCDM\ counterpart. We are able to identify a
series of small correlations between the coupling in the dark sector and halo
spin, triaxiality and virialization ratio. When looking at spin and
virialization of dark matter haloes, we find a weak ($5\%$) but systematic
deviation in fifth force scenarios from \LCDM.

Cosmology and Nongalactic Astrophysics