Conformational stability, vibrational (FT-IR and FT-Raman) spectra and computational analysis of m-trifluoromethyl benzoic acid

• Optimized geometrical parameters of mTFBA obtained by B3LYP, LSDA and MP2 methods.
• Global minimum energy for four conformers of mTFBA have been studied.
• HOMO and LUMO analysis have been calculated.
• Electrostatic potential surface have been calculated.
• Thermodynamic parameters have been calculated.

In this work, the vibrational characteristics of m-trifluoromethyl benzoic acid have been investigated and both the experimental and theoretical vibrational data indicate the presence of functional groups in the title molecule. The density functional theoretical (DFT) computations were performed at the B3LYP/6-31G (d, p), LSDA/6-31G (d, p), MP2/6-31G (d, p) levels to derive the optimized geometry, vibrational wavenumbers. Furthermore, the molecular orbital calculations such as natural bond orbitals (NBO), HOMO–LUMO energy gap and Mapped molecular electrostatic potential (MEP) surfaces, The Mulliken charges, the first-order hyperpolarizability were also performed with the same level of DFT. The thermal flexibility of molecule in associated with vibrational temperature was also illustrated on the basis of correlation graphs. The detailed interpretation of the vibrational spectra has been carried out with the aid of potential energy distribution (PED) results obtained from MOLVIB program. The delocalization of electron density of various constituents of the molecule has been discussed with the aid of NBO and HOMO–LUMO energy gap analysis.

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