Molecular structural, non-linear optical, second order perturbation and Fukui studies of Indole-3-Aldehyde using density functional calculations

Indole-3-Aldehyde is a new organic non-linear material having good second harmonic generation. The optimized molecular geometry, harmonic vibrational frequencies, infrared intensities of Indole-3-Aldehyde (I3A, C9H7NO) in the ground state were carried out by using density functional theory (B3LYP) method with 6-31G(d,p) basis set. A detailed interpretation of the infrared spectrum of Indole-3-Aldehyde is reported. The vibrational frequencies are calculated and compared with experimental FT-IR spectra. The theoretical spectrograms of FT-IR of the title compound have been constructed in addition, theoretical information like ONIOM, potential energy surface, NBO, and Fukui function are also calculated. Unambiguous vibrational assignment of all the fundamentals was made using the potential energy distribution.

Graphical abstractThe optimized molecular geometry and bond order of Indole-3-Aldehyde (I3A, C9H7NO) and its divalent cation (I3A2+, C9H7NO2+) in the ground state were carried out by using density functional theory (DFT/B3LYP) method with 6-31G(d,p) basis set.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Indole-3-Aldehyde (I3A) is a new organic non-linear material having good SHG. ► Belongs to non-centrosymmetric space group has 18 atoms with 48 normal modes. ► Vibrational assignments were made using the potential energy distribution.