Towards the Assessment of Chemical Reactivity in Excited States through Conceptual Density Functional Theory using the ΔSCF Approach

As one of the best-established and accepted chemical reactivity theories, conceptual density
functional theory has gained tremendous acceptance in characterizing ground state chemical
reactions. Owing to recent advances in the foundation of the ΔSCF method in density functional
theory, it is now possible to establish a mathematically rigorous reactivity theory associated with it
namely the excited state conceptual density functional theory (exCDFT). In this proposal, we thus
utilize the ΔSCF method to obtain accurate reactivity indices as well as other well-known molecular
properties for excited states. To enhance its practicality, semiempirical tight binding approaches will
be further extended to the investigation of excited state properties for large systems with a few
illustrative practical applications. In terms of the accuracy of density functional (tight binding)
approaches, the localized orbital scaling correction will be applied to revise the systematic
delocalization error of density functional approximations. All developing theories will be implemented
in an efficient and free software package for future applications.