Structural, electronic and vibrational properties of DL-histidine

In the present work, the structural, electronic and vibrational characteristics of zwitterionic DL-histidine have been investigated using DFT calculations and IR spectroscopy. The molecular structure of DL-histidine has been optimized in aqueous solution and in the solid phase. A good agreement between the experimental structural parameters (bond lengths and angles) obtained by X-Ray diffraction and the calculated ones in the solid phase is achieved. Some interesting electronic properties like the HOMO and LUMO energies and HOMO-LUMO energy gap have been predicted in the liquid phase using water as solvent. The experimental IR spectrum has been recorded and interpreted employing DFT calculations.