  We analyze a new fundamental building block for monolithic nanoengineering on
graphene: the Inverse-Stone-Thrower-Wales (ISTW) defect. The ISTW is formed
from a pair of joined pentagonal carbon rings placed between a pair of
heptagonal rings; the well-known Stone-Thrower-Wales (STW) defect is the same
arrangement, but with the heptagonal rather than pentagonal rings joined. When
removed and passivated with hydrogen, the structure constitutes a new molecule,
diazulene, which may be viewed as the result of an ad-dimer defect on
anthracene. Embedding diazulene in the honeycomb lattice, we study the effect
of ad-dimers on planar graphene. Because the ISTW defect has yet to be
experimentally identified, we examine several synthesis routes and find one for
which the barrier is only slightly higher than that associated with adatom
hopping on graphene. ISTW and STW defects may be viewed as fundamental building
blocks for monolithic structures on graphene. We show how to construct extended
defect domains on the surface of graphene in the form of blisters, bubbles, and
ridges on a length scale as small as 2 angstroms by 7 angstroms. Our primary
tool in these studies is density functional theory.
