THz vibrational spectra of selected tripeptides: experiments and theory

We use terahertz time-domain spectroscopy to determine the room temperature THz spectrum of different tripeptides (glutathione, gly-gly-gly and enalapril maleate). Several molecular resonances are observed which we attribute to intramolecular vibrational modes. The experimental data are compared to density functional theory (DFT) calculations.