For instance, for single
crystals of graphite only one line can be observed at 1580 5 cm1
(G line), which is assigned to the E2g variety of the infinite crystal.
For other materials like stress-annealed pyrolitic graphite,
commercial graphites, activated charcoal, lampblack, and vitreous
carbon another line can be found at 1355 cm1 (D line) [9]. This
band is attributed to the A1g variety of the small crystallites or
boundaries of larger crystallites of graphite; it becomes Raman
active due to the finite crystal size. The Raman intensity of this band
is inversely proportional to the crystallite size and is caused by