Characteristic regions on the energy landscape of MgF2

High-dimensional energy landscapes of complex systems often exhibit a very complicated structure, with many local minima separated by a multitude of b arriers of various heights. For the analysis of the dynamics on such landsc apes, simplified models based on combining many microstates to form physica lly relevant macrostates are of great advantage. In particular, knowledge o f the relative sizes of minimum and transition regions is crucial. As an ex ample, we analyse transitions in low-energy regions belonging to a simple m odel of the crystalline compound MgF2. We find that the minimum regions, i. e. the states associated with only one particular minimum, extend to energi es far above the saddle points, and we show that the size of the transition regions is small compared with the minimum regions.