Density functional theory studies on molecular structure, vibrational spectra and electronic properties of cyanuric acid

• FT-IR and FT-Raman investigations of cyanuric acid were carried out.
• NBO analysis used to explain the interaction between electron donors and acceptors.
• The atomic charges on the various atoms of molecule were obtained by Mulliken population analysis.
• Thermodynamic parameters of the title molecule are reported.

The present work has been carried out a combined experimental and theoretical study on molecular structure, vibrational spectra and NBO analysis of cyanuric acid. The FT-IR (100–4000 cm−1) and FT-Raman spectra (400–4000 cm−1) of cyanuric acid were recorded. In DFT methods, Becke’s three parameter exchange-functional (B3) combined with gradient-corrected correlation functional of Lee, Yang and Parr (LYP) by implementing the split-valence polarized 6-31G(d,p) and 6-31++G(d,p) basis sets have been considered for the computation of the molecular structure optimization, vibrational frequencies, thermodynamic properties and energies of the optimized structures. The density functional theory (DFT) result complements the experimental findings. The electronic properties, such as HOMO–LUMO energies and molecular electrostatic potential (MESP) are also performed. Mulliken population analysis on atomic charges is also calculated. The first order hyperpolarizability (βtotal) of this molecular system and related properties (β, μ and Δα) are calculated using DFT/B3LYP/6-31G (d,p) and B3LYP/6-311++G(d,p) methods. The thermodynamic functions (heat capacity, entropy and enthalpy) from spectroscopic data by statistical methods were also obtained for the range of temperature 50–1000 K.

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