The Wonderful World of Molecular Anions

I am going to tell you about several classes of molecular anions whose chemical and physical behaviors will, I believe, be surprising to you. First, I'll show you some anions in which the excess electron does not go into the molecular orbital that I think most in the audience will predict, and I will tell you how such anions are playing important roles in modern chemistry research. Next, I will show you how internal Coulomb repulsion among the negative sites in multiply charged anions gives rise to (1) certain molecular anions that we chemists usually treat as stable well known species not existing at all for very long times; and (2) some anions undergoing photo-detachment processes in which the ejected electron has higher kinetic energy than the energy of the photon used to cause the photo-detachment. Finally, I will tell you about an interesting research project aimed at understanding (1) how very low-energy electrons (e.g., with kinetic energies of ca. 25 kcal/mol) can cause strong (ca. 100 kcal/mol) bonds in DNA to break. This project relates to experimental findings in which such low-energy electrons cause so-called strand breaks in DNA; before our studies, researchers did not know how this could happen nor did they know which covalent bonds in the DNA were cleaved.

A good overview of much of this material and more can be found in this 110 page article by the speaker: J. Phys. Chem. A 112, 6401-6511, Molecular Anions, J. Simons