Construction of the free energy landscape by the density functional approarch

We propose a new method to construct the free energy landscape in the configurational space, where the density functional approach to the thermodynamic function is exploited. In order to demonstrate the validity of the method, we construct the free energy landscape for rearrangement of atoms in an FCC crystal of hard spheres. Analyzing the relaxation process, we deduce two concepts of rearranging region, one is the simultaneously rearranging region (SRR) which is defined by the difference between two adjacent regions. The other is the cooperatively rearranging region (CRR) which is the spheres involved in the saddle configuration between two adjacent regions. The latter region corresponds to the region introduced by Adam and Gibbs. We show that the SRR and the CRR can be determined explicitly from the free energy landscape.