the assumption that electron attachment or detachment occurs much more rapidly than atomic rearrangement. Calculating a vertical electron affinity (EA) or ionization energy (IE) therefore requires only a single-point energy calculation on an optimized geometry with the charge shifted by -1 (for EA) or +1 (for IE). Since vertical EA and IE calculations involve only a single molecular structure, they can be calculated using a single MoleculeDoc and its associated tasks.