Perspectives on theoretical tools for studying molecular anions

In this perspective article, I offer thoughts about the development and evolution of four theoretical chemistry tools in which my research group has been involved that have proven useful in the study of molecular anions. These tools are (i) the equations of motion methods for directly calculating the intensive electron affinity rather than by subtracting the extensive anion's energy from the extensive neutral molecule's energy; (ii) systematic methods for creating extra diffuse atomic orbital basis functions for use in studying dipole-bound anions; (iii) analytical expressions for rates and associated angular distributions of electrons ejected by way of vibration/rotation energy transfer; and (iv) methods by which energies and lifetimes of electronically metastable anions can be determined using conventional quantum chemistry tools. I also offer suggestions for future enhancements within these research areas that I think are worth pursuing, hopefully inspiring younger theoretical chemists to do so.