Properties of Ions and Ion-Molecule Complexes

 Ions are vital to almost all of chemistry.  From biochemistry to material science you find that ions are deeply involved in the chemistry.  Often, an ion and a neutral molecule are strongly attracted to each as an ion-molecule complex.  Calculating accurate potential energy surfaces for ions interacting with molecules is a challenging problem and such calculations provide important information for modeling the formation of ion-molecule complexes.  These types of calculation require careful attention to the quality of the calculation so that potential energy surface is accurate over a wide range of geometries for the interacting species.

 In addition, we are particularly interested in negative ions.  These ions offer two challenges for computational  chemists.  First, because of the extra electron more care is often required in calculating the properties of these ions, and second, some anions are metastable (meaning that after a short time they spit out the extra electron because the neutral molecule is more stable than the anion).  Presently we are exploring negative ions of molecules that have large quadrupole moments.  Such molecules have two means of attracting the extra electron: the typical idea of an electron being captured into a normally empty orbital and the additional attraction to the quadrupole moment.  There has been continued interest in exploring the roles of these two means of attraction.