Jc. Grossman et al., STRUCTURE AND STABILITY OF MOLECULAR CARBON - IMPORTANCE OF ELECTRON CORRELATION, Physical review letters, 75(21), 1995, pp. 3870-3873
The electronic structure of medium-size molecular carbon is determined
by a variety of methods, including density functional, quantum chemis
try, and quantum Monte Carlo approaches. We demonstrate (i) significan
t differences between the mean-field methods in determining the minimu
m energy structure of a set of C-10 and C-20 isomers, and (ii) the cru
cial importance of an accurate account of electron correlation which e
nables us to predict, e.g., that of the available geometries for C-20
the relaxed graphite fragment (bowl) is lower in energy than either th
e ring or fullerene isomers.