Molecular structure, spectroscopy (FT-IR, FT-Raman), thermodynamic parameters, molecular electrostatic potential and HOMO-LUMO analysis of 2, 6-dichlorobenzamide

• FT-IR and FT-Raman spectra of 2, 6-dichlorobenzamide were recorded and analyzed.
• Complete vibrational assignments were made by PED analysis.
• HOMO, LUMO energies and MEP were studied.
• Thermodynamic parameters in various temperatures are calculated.

2, 6-dichlorobenzamide is the degradation product of 2, 6-dichlorobenzonitrile, which is often used as herbicide and can cause groundwater pollution. The FT-IR and FT-Raman spectra of 2, 6-dichlorobenzamide at room temperature were recorded and analyzed in the range 4000–400 and 3700-100 cm−1, respectively. In order to obtain the most stable structure, a potential energy surface (PES) scan for internal rotations was carried out at the B3LYP/6-31G(d) level. The optimized geometry, structural parameters energies, theoretical IR and Raman spectra for the title compound have been obtained by employing B3LYP exchange-correlation functional with high-quality aug-cc-pVTZ basis-set. Detailed vibrational assignments of vibrational spectra have been made on the basis of the potential energy distributions (PED) analysis. In addition, the HOMO-LUMO gap and molecular electrostatic potential (MEP) were studied theoretically. Finally, the thermodynamic functions (heat capacity, entropy, enthalpy, and Gibbs free energy) of 2, 6-dichlorobenzamide were obtained in the range of 100–1000 K.

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