Abstract
Density functional theory (DFT) has become an extensively and successfully used tool in the studies of molecules and materials. However, DFT remains computationally expensive, especially for molecular systems comprising a few hundred atoms. Here, we present a Robust Approximate Density-functional Expansion (RADE) method, devised to substantially reduce the computational cost of conventional DFT. RADE can be implemented fully non-empirically as an efficient first-principles electronic structure method. Preliminary results for molecules containing elements H, C, N, and O indicate that this method can in general reproduce well the results from conventional DFT calculations.