This study in the Theoretical and Computational Chemistry Program of the Chemistry Division is supported through the NSF Young Investigator Awards Program and involves the formulation and implementation of new electronic structure methods for calculating electronically excited states for both molecules and gas-surface systems. Further, connections are being sought to dynamical theories to allow first-principles predictions of energy flow in, and the chemical reactivity of, such excited states. %%% In this study supported by the NSF Young Investigator Awards Program new theoretical and computational methods are being developed for describing the excited electronic states and the chemical reactivity of molecules in the gas phase or on surfaces.