Molecular structure, FT-IR and FT-Raman spectra and HOMO- LUMO analysis of 2-methoxy-4-nitroaniline using ab initio HF and DFT (B3LYP/B3PW91) calculations
نویسنده
چکیده
Fourier-Transform infrared and Fourier-Transform Raman spectra of 2-methoxy-4nitroaniline(2M4NA) was recorded in the region 4000 – 400 cm and 3500 – 100 cm .Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of 2M4NA were carried out by ab initio HF/6-311G(d,p) and DFT (B3LYP/6-311G(d,p) and B3PW91/6-311G(d,p)) levels of theory with complete relaxation in the potential energy surface.The vibrational frequencies are calculated and scaled values are compared with FT-IR and FT-Raman experimental values. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small in DFT than HF. The calculated HOMO-LUMO energies show that charge transfer occurs in the molecule. The study is extended to the HOMO LUMO analysis to calculate the energy gap, ionization potential, electron affinity, global hardness,chemical potential and global electrophilicity and thermodynamic properties of 2M4NA.. The experimental spectra also coincide satisfactorily with those of theoretically constructed simulated spectrograms.
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Computation and interpretation of vibrational spectra, thermodynamical and HOMO-LUMO analysis of 2-chloro-4-nitroaniline
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