Dipole-Bound Anions of Glycine Based on the Zwitterion and Neutral Structures

The instability of the zwitterion structure of glycine is significantly reduced by the attachment of an excess electron as a result of which a local minimum develops on the anionic potential energy surface for the zwitterion structure. However, the global anionic minimum, which is lower by 9 kcal/mol, corresponds to a singly hydrogen-bonded nonzwitterion structure. The vertical electron detachment energies for these two dipole-bound zwitterion and nonzwitterion structures are 3175 and 668 cm - 1, respectively.