In this project, we will continually focus on the first-principles simulations of nano-electronics and photonics. Specifically, we will further develop a multi-level theoretical framework, in which accurate first-principles calculations could be coupled with theories of different levels, such as quantum electrodynamics, Maxwell equations, density matrix equations, non-equilibrium Green’s function theory, to study the plasmonic effect on novel optical response of molecules in nano-cavity as well as various x-ray spectra for molecules, materials, and interfaces. The development of the theory and corresponding computational packages will not only be helpful to our understanding of many new phenomena reported in experiments, but also lead to important theoretical predictions such as the breakdown of both symmetry and spin selection rule by localized plasmonic field that provides a unique tool to rationally manipulate molecular excited states. We will also focus on the mechanism for photocatalytic reduction of CO2 on the TiO2 surface and thus design better catalyst for global warming and energy crisis. All of these projects require heavy computations and the progress will depend severely on the computational resources.