FTIR, FT-Raman and UV-Vis spectral studies of d-tyrosine molecule

In the present work, experimental and theoretical studies on the structure, vibrational spectra and electronic spectra of d-tyrosine molecule are reported. The FTIR (4000-400 cm−1) and FT-Raman (4000-50 cm−1) spectra were recorded and analysed using anharmonic frequency calculations at PT2-VSCF and VPT2 levels in gas and solution phases. The solute-solvent interactions were treated using the integral equation formalism of the polarisation continuum model (IEF-PCM). The calculated anharmonic frequencies were compared with the experimental ones. It was found that PT2-VSCF anharmonic frequencies are closer to the experimental data. The VPT2 frequencies in gas and solution phases have small differences. The magnitudes of coupling between pair of modes were also computed. In addition, studies on the excitation energies, oscillator strengths, HOMO and LUMO energies and MEP of d-tyrosine at TD-DFT level are also reported.