  Cosmological hydrodynamical simulations of galaxy clusters are still
challenged to produce a model for the intracluster medium that matches all
aspects of current X-ray and Sunyaev-Zel'dovich observations. To facilitate
such comparisons with future simulations and to enable realistic cluster
population studies for modeling e.g., non-thermal emission processes, we
construct a phenomenological model for the intracluster medium that is based on
a representative sample of observed X-ray clusters. We create a mock galaxy
cluster catalog based on the large collisionless N-body simulation MultiDark,
by assigning our gas density model to each dark matter cluster halo. Our
clusters are classified as cool-core and non cool-core according to a dynamical
disturbance parameter. We demonstrate that our gas model matches the various
observed Sunyaev-Zel'dovich and X-ray scaling relations as well as the X-ray
luminosity function, thus enabling to build a reliable mock catalog for present
surveys and forecasts for future experiments. In a companion paper, we apply
our catalogs to calculate non-thermal radio and gamma-ray emission of galaxy
clusters. We make our cosmologically complete multi-frequency mock catalogs for
the (non-)thermal cluster emission at different redshifts publicly and freely
available online through the MultiDark database (www.multidark.org).
