  Motivated by the novel electronic behaviors seen in transition metal oxides,
we look for physical insight into disordered, strongly-correlated systems by
exploring the atomic limit. In recent work, the atomic limit has provided a
useful reference point in systems with strong {\em local} interactions. For
comparison with experiments, the exploration of {\em non}local interactions is
of interest. In the atomic limit, both the case of on-site interactions alone
and the case of infinite-range ($1/r$) interactions are well understood;
however, not so the intervening possibilities. Here we study the atomic limit
of the extended Anderson-Hubbard model using classical Monte Carlo to calculate
the single-particle density of states. We show that the combination of
nearest-neighbor interactions and site disorder produce a zero-bias anomaly
caused by residual charge ordering, and the addition of on-site interactions
has a non-monotonic effect on the depth of this zero-bias anomaly. A key
conclusion is that the form of the density of states in this classical system
strongly resembles density of states results obtained for the full extended
Anderson-Hubbard model when $U<4V$.
