9810620 Perdew This award supports theoretical research on the properties of atoms, molecules, and solids. The proposed work focuses on improving the methods and concepts of density functional and pseudopotential theory. Specific projects include: (1) Incorporate the second derivative in the generalized gradient expansion for the exchange correlation energy in a way that recovers the fourth-order gradient expansion for the exchange energy in the limit of slow or long-wavelength density fluctuations. (2) Construct a similar "Laplacian level GGA" for the kinetic energy. (3) Construct an electron- ion pseudopotential that provides a correct description of the interaction between core and valence electrons. (4) Develop models based on the generalized gradient approximation and beyond for the exchange-correlation hole. (5) Study exchange and correlation in the low-density or strongly-correlated limit. (6) Test various density functionals for the quasi-two-dimensional electron gas or quantum well to see if they satisfy one-dimensional density scaling. (7) Propose a simplified equation of state for solids. (8) Develop and test a fully nonlocal orbital functional for the correlation energy, compatible with exact exchange. %%% Perdew will use analytical and numerical techniques to improve density-functional based theories of materials and of the electronic structure of atoms, molecules, and solids. The work has potential to broadly impact research efforts as well as simulation methods applied to a wide variety of materials and phenomena that occur in materials. ***
