Wavenumber (cm─1) Wavenumber (cm─1) Vibration Functional group or component
FTIR-PAS FTIR-ATR
3900−3700 - νO─H Clay minerals (Churchman et al., 2010; Xing et al., 2019)
3620 νO─H Clay minerals (Xu, Du, Ma, Shen, & Zhou, 2020)
3600−3400 3600−3000 νO─H, N─H Water, alcohols, and phenols; carboxyl and hydroxyl groups, amides (Ellerbrock & Gerke, 2004; Pedersen, Simpson, Bockheim, & Kumar, 2011)
3000−2800 - νC─H Aliphatic methyl and methylene groups (Ellerbrock & Gerke, 2004; Soriano-Disla, Janik, Viscarra Rossel, Macdonald, & McLaughlin, 2014)
2200−2000 2200−2000 Overtone νCOH Carbohydrates (Janik, Skjemstad, Shepherd, & Spouncer, 2007)
1720−1600 1720−1600 νC═O, νC═C Carboxylic acids; amides; Aromatics (Changwen Du, Goyne, Miles, & Zhou, 2014; C. Du, Linker, & Shaviv, 2007)
- 1570–1540 νN─H, νC─N in plane Amide II (Calderón, Haddix, Conant, Magrini-Bair, & Paul, 2013) (Leifeld, 2006)
1515 1515 νC═C Aromatics (Calderón et al., 2013)
- 1500−1300 νCO32− Carbonates (Viscarra Rossel & Behrens, 2010)
1445−1350 - νC─H Methyls (Janik et al., 2007; Rossel & Behrens, 2010)
- 1160 νC─O Polysaccharides, nucleic acids, proteins (Calderón et al., 2013)
- 1050 δC─O Carbohydrates (Movasaghi, Rehman, & ur Rehman, 2008; Viscarra Rossel & Behrens, 2010)
1030-950 990 νSi─O Clay minerals (Madejová, 2003)
- 915 δAl─OH Kaolinite and smectite (Viscarra Rossel & Behrens, 2010)
850 - NH2 out of plane Primary amine (Smidt & Meissl, 2007)
- 770 NH2 out of plane Primary amine (Nayak & Singh, 2007)