“…The band centered at 1530 cm À1 consists of two sub-bands, one centered at 1480 and the second at 1570 cm À1 . Generally, the bands centered at 1150 and 1480 cm À1 are often assigned to the nanocrystalline character of diamond deposits [20,21]. Pfeiffer et al demonstrated that these bands can most probably be attributed to the presence of trans-polyacetylene segments located at the grain boundaries [22].…”