  We study fluid structure and water-like anomalies of a system constituted by
dimeric particles interacting via a purely repulsive core-softened potential by
means of integral equation theories. In our model, dimers interact through a
repulsive pair potential of inverse-power form with a softened repulsion
strength. By employing the Ornstein-Zernike approach and the reference
interaction site model (RISM) theory, we study the behavior of water-like
anomalies upon progressively increasing the elongation {\lambda} of the dimers
from the monomeric case ({\lambda} = 0) to the tangent configuration ({\lambda}
= 1). For each value of the elongation we consider two different values of the
interaction potential, corresponding to one and two length scales, with the aim
to provide a comprehensive description of the possible fluid scenarios of this
model. Our theoretical results are systematically compared with already
existing or newly generated Monte Carlo data: we find that theories and
simulations agree in providing the picture of a fluid exhibiting density and
structural anomalies for low values of {\lambda} and for both the two values of
the interaction potential. Integral equation theories give accurate predictions
for pressure and radial distribution functions, whereas the temperatures where
anomalies occur are underestimated. Upon increasing the elongation, the RISM
theory still predicts the existence of anomalies; the latter are no longer
observed in simulations, since their development is likely precluded by the
onset of crystallization. We discuss our results in terms of the reliability of
integral equation theories in predicting the existence of water-like anomalies
in core-softened fluids.
