  Exciton condensation, a Bose-Einstein condensation of excitons into a single
quantum state, has recently been achieved in low-dimensional materials
including twin layers of graphene and van der Waals heterostructures. Here we
examine computationally the beginnings of exciton condensation in a double
layer comprised of coronene, a seven-benzene-ring patch of graphene. As a
function of interlayer separation, we compute the exciton population in a
single coherent quantum state, showing that the population peaks around 1.8 at
distances near 2 \AA. Visualization reveals interlayer excitons at the
separation distance of the condensate. We determine the exciton population as a
function of the twist angle between the two coronene layers to reveal the magic
angles at which the condensation peaks. As with previous recent calculations
showing some exciton condensation in hexacene double layers and benzene stacks,
the present two-electron reduced-density-matrix calculations with coronene
provide computational evidence for the ability to realize exciton condensation
in molecular-scale analogs of extended systems like the graphene double layer.
