NBO, NLO, HOMO–LUMO, NMR and Electronic spectral study on 1-Bromo-4-Methyl Naphthalene Quantum Computational and Spectroscopic (FT-IR, FT-Raman) Methods
The spectra of 1-bromo-4-methylnaphthalene have been analyzed in the region 4000–400 and 4000–100 cm−1for FTIR and FT-Raman respectively. The optimized geometry, fundamental vibrational frequency and intensity of the vibrational bands of title compound were evaluated using ab initio HF and density functional theory (DFT) levels of theory 6-311G basis set. The Calculated harmonic vibrational frequencies were scaled and the values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies were found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed spectrograms. Mullikan atomic charge were calculated and interpreted. A study on the electronic properties, such as HOMO and LUMO energies were performed by time independent DFT approach. In addition, molecular electrostatic potential (MEP) and thermodynamic properties were performed. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by gauge independent atomic orbital (GIAO) method and compared with experimental chemical shift of closely related molecules. First order hyperpolarizability and polarizability of title compound were calculated using HF theory. Thermodynamic calculations of title compound were also performed with different temperature.
