FT-IR, FT-Raman and UV spectral investigation; computed frequency estimation analysis and electronic structure calculations on 1-nitronaphthalene

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 100–4000 cm−1 and 400–4000 cm−1 respectively, for 1-nitronaphthalene (C10H7NO2) molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based density functional theory (DFT) and ab initio HF methods and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of total energy distribution (TED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) complements with the experimental findings. Thermodynamic properties of the title compound at different temperatures have been calculated. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) were performed.

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► Spectroscopic properties of Nitronaphthalene were examined by DFT method.
► All results were compared with experimental FT-IR and FT-Raman spectra.
► HOMO and LUMO, absorption wavelength and excitation energies were performed.
► The important thermodynamical parameters are reported.
► Molecular electrostatic potential distribution of Nitronaphthalene was calculated.