This project supports efforts in electronic structure theory and non-equilibrium statistical mechanical & multiscale modeling. The primary focus is on the development and application of methods that enable the study of condensed-phase chemistry and surface reaction phenomena, especially heterogeneous catalysis. Also of interest are solvent effects, homogeneous organometallic catalysis, and excited states and photocatalysis in large molecular systems. Electronic structure theory efforts integrate development of fundamental theory, expanding the capability for accurate treatment of large systems of interest to USDOE BES, with optimal strategies for computational implementation within GAMESS. Theory development includes fragment molecular orbital, effective fragment molecular orbital and effective fragment potential approaches with applications to liquid-solid interfaces, and embedding methods for solid surfaces. Statistical mechanical and multiscale modeling studies also focus on catalytic reaction-diffusion phenomena. This modeling often incorporates input from relevant electronic structure analyses. A core focus in this effort is on molecular-level and coarse-grained modeling the interplay between restricted transport and catalytic reaction in functionalized nanoporous materials. Another major effort is on the predictive molecular-level modeling of chemisorption and heterogeneous catalysis on metal surfaces and nanoclusters (exploring catalytic poisoning, fluctuation-dominated and spatiotemporal behavior). In addition, our modeling explores the synthesis and stability of catalytic nanomaterials.