On the spectroscopic analyses of aspartic acid

Abstract

Aspartic acid was subjected to quantum mechanical calculations at B3LYP/3-21G**. The amino acid was tested in gaseous phase then in the existence of two water molecules and when interacted with monovalent metal (Na) and then two units were made to interact with divalent metal (Cd). Vibrational frequencies bands were shifted into higher wavenumber as a result of hydration. The same was noticed also when Na interacted with aspartic acid through the hydrogen bonding of COOH group. The change in geometrical parameters was discussed in terms of changes in the COOH and NH2 groups. The molecular point group was corresponding to C1 point group for all the studied structures. The calculated total dipole moment increases as a result of complexation while slightly increased in case of hydration. Finally, the band gap energy decreases as a result of hydration and then further decreases as a result of complexation.