Ab initio theoretical study of dipole-bound anions of molecular complexes: formaldehyde dimer anion

Theoretical ab initio calculations reveal that when two formaldehyde molecules form a cluster with a collinear orientation of their dipoles and a perpendicular orientation of their planes, an excess electron can attach to the system forming a dipole-bound anion. This configuration is a local minimum on the anion potential energy surface (PES) and the vertical electron detachment energy of the anion at this point is predicted to be 20 meV. However, calculations of the PES near the minimum revealed that it does not support the zero-point vibration corresponding to the bending mode of the complex.