“…A rather broad but weak plateau between 1400 and 1000 cm À1 with some distinct bands at 1260, 1243, 1180, 1154, 1077, and 1031 cm À1 is caused by a series of absorptions due to different functional groups like CÀH, CÀOÀC, CÀOH, and CÀC. Morterra & Low (1983, 1985 attributed a broad band around 1260 cm À1 to ether-like CÀO bonds cross-linking polyaromatic and also aliphatic domains, but the authors also mentioned that the band is a summation of absorptions due to species with and without oxygen. However, an exact assignment of bands in this broad plateau to special groups remains speculative since there are a lot of different functional groups with single bonds integrated in varying chemical environments, leading to a distribution of vibrational bands in this spectral range.…”