  We study a monomer-dimer model with repulsive interactions between the same
species in one dimension. With infinitely strong interactions the model
exhibits a continuous transition from a reactive phase to an inactive phase
with two equivalent absorbing states. Static and dynamic Monte Carlo
simulations show that the critical behavior at the transition is different from
the conventional directed percolation universality class but is consistent with
that of the models with the mass conservation of modulo 2. The values of static
and dynamic critical exponents are compared with those of other models. We also
show that the directed percolation universality class is recovered when a
symmetry-breaking field is introduced.
