  In this paper, we offer large and realistic models of amorphous carbon
spanning densities from 0.95 g/cm3 to 3.5 g/cm3 . The models are designed to
agree as closely as possible with experimental diffraction data while
simultaneously attaining a local minimum of a density functional Hamilto- nian.
The structure varies dramatically from interconnected wrapped and defective sp2
sheets at 0.95 g/cm3 to a nearly perfect tetrahedral topology at 3.5 g/cm3 .
Force Enhanced Atomic Refine- ment (FEAR) was used and is shown here to be
computationally superior and more experimentally realistic than conventional ab
initio melt quench methods. We thoroughly characterize our models by computing
structural, electronic and vibrational spectra. The vibrational density of
states of the 0.95 g/cm3 model is strikingly similar to monolayer amorphous
graphene. Our sp2 /sp3 ratios are close to experimental predictions where
available, a consequence of compelling a satisfactory fit for pair correlation
function.
