Table 1 Calculated IR frequencies for HA which calculated at B3LYP/6-31G(d, p), in comparison with FTIR spectrum of HA.
From: DFT insights into humic acid coordination of Cd(II) Cu(II) and Pb(II)
Calculated IR (cm− 1) | FTIR (cm− 1) | Band assignment | |
|---|---|---|---|
Unscaled | Scaled | ||
497.9 | 482.0 | 472 | CH deformation vibration |
656.0 | 635.2 | 618 | N-H bending |
873.8 | 845.7 | 800 | CH deformation vibration |
1118.6 | 1082.7 | 993 | CH vibration |
1181.3 1195.6 | 1143.3 1157.2 | 1158 | CH vibration |
1398.5 1416.0 | 1353.6 1370.5 | 1380 | Methyl symmetric bending vibration |
1668.4 | 1614.9 | 1640 | C = C stretching vibration |
1776.3 1818.7 | 1719.3 1760.3 | 1721 | C = O |
3186.5 | 3084.2 | 2800 2900 | CH vibration |
3749.7 3766.9 | 3629.3 3646.0 | 3300 3400 | OH |
