Density functional theory, restricted Hartree – Fock simulations and FTIR, FT-Raman and UV–Vis spectroscopic studies on lamotrigine

• FTIR and FT Raman analysis of lamotrigine in the solid state were recorded and analyzed.
• The optimized geometry and vibrational spectrum was computed using DFT and RHF methods.
• The vibrational assignment and spectroscopic analysis have been carried out.
• Natural and Mulliken population analysis of the molecule are obtained by Natural Bonding orbital method (NBO).
• The DFT calculated HOMO and LUMO energies show that charge transfer occurs within molecule.

The Fourier Transform Infrared (FTIR) and FT Raman spectra of lamotrigine have been recorded in the region 4000–450 cm−1 and 4000–50 cm−1, respectively. The title compound is used as Antiepileptic drug. The optimized geometry, frequency, and intensities of the vibrational bands of the lamotrigine were obtained by Density Functional Theory (DFT) using B3LYP/631G** basis set and ab initio method at the restricted Hartree Fock/6-31** level. The harmonic vibrational frequencies, Natural population analysis, HOMO–LUMO energy gap, infra red intensities and Raman scattering activities, force constant were calculated by DFT and RHF methods. The quality of lamotrigine under different storage containers were analyzed using UV–Vis spectral technique.

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