We show that molecular dynamics based moves in the Minima Hopping (MH) method are more efficient than saddle point crossing moves which select the lowest possible saddle point. For binary systems we incorporate identity exchange moves in a way that allows to avoid the generation of high energy configurations. Using this modified Minima Hopping method we reexamine the binary Lennard Jones (BLJ) benchmark system with up to 100 atoms and we find a large number of new putative global minima structures.

Based on a recently introduced metric for measuring distances between configurations, we introduce distance-energy (DE) plots to characterize the potential energy surface of clusters. Producing such plots is computationally feasible on the density functional level since it requires only a few hundred stable low energy configurations including the global minimum. By using standard criteria based on disconnectivity graphs and the dynamics of Lennard-Jones clusters, we show that the DE plots convey the necessary information about the character of the potential energy surface and allow us to distinguish between glassy and nonglassy systems. We then apply this analysis to real clusters at the density functional theory level and show that both glassy and nonglassy clusters can be found in simulations. It turns out that among our investigated clusters only those can be synthesized experimentally which exhibit a nonglassy landscape.

Surfaces and interfaces of bulk materials with liquids are of importance for a wide range of chemical processes.In this work, we systematically explore reconstructions on the (100) surface of calcium fluoride (CaF 2 ) and other fluorites (MF 2 ), M = {Sr,Cd,Ba} by sampling the configurational space with the minima hopping structure prediction method in conjunction with density functional theory calculations. We find a large variety of structures that are energetically very close to each other and are connected by very low barriers, resulting in a high mobility of the topmost surface anions. This high density of configurational states makes the CaF 2 (100) surface a very dynamic system. The majority of the surface reconstructions found in CaF 2 are also present in SrF 2 , CdF 2 , and BaF 2 . Furthermore, we investigate in detail the influence of these reconstructions on the crystal growth of CaF 2 in solvents by modeling the fluorite-water interface and its wetting properties. We perform a global structural search both by explicitly including water molecules and by employing a recently developed soft-sphere solvation model to simulate an implicit aqueous environment. The implicit approach correctly reproduces both our findings with the explicit-water model and the experimentally reported contact angles for the partial-hydrophobic (111) and hydrophilic (100) surfaces. Our simulations show that the high anion mobility and the low coordination of the (100) surface atoms strongly favors the adsorption of water molecules over the (111) surface. The aqueous environment makes terminations with low-coordination surface atoms more stable, promoting (100) growth instead of the (111).

Based on a recently introduced metric for measuring distances between configurations, we introduce distance-energy (DE) plots to characterize the potential energy surface (PES) of clusters. Producing such plots is computationally feasible on the density functional (DFT) level since it requires only a set of a few hundred stable low energy configurations including the global minimum. By comparison with standard criteria based on disconnectivity graphs and on the dynamics of Lennard-Jones clusters we show that the DE plots convey the necessary information about the character of the potential energy surface and allow to distinguish between glassy and non-glassy systems. We then apply this analysis to real systems on the DFT level and show that both glassy and non-glassy clusters can be found in simulations. It however turns out that among our investigated clusters only those can be synthesized experimentally which exhibit a non-glassy landscape.