Pair natural orbital and canonical coupled cluster reaction enthalpies involving light to heavy alkali and alkaline earth metals: the importance of sub-valence correlation

The sub-valence electron correlation effects are of critical importance for accurate energetics of alkali and alkaline-earth complexes from (DLPNO-)CCSD(T) calculations.

About the diffusion mechanism in the silica liquid

In this paper, we have numerically studied the diffusion mechanism in silica liquid based on the idea that the collective movement of particles is controlled by reactions [Formula: see text] and [Formula: see text]. Four models at temperatures from 2600 K to 3500 K have been constructed by molecular dynamic simulation. The simulation shows that the liquid has a small amount of defect-cells which are of importance for the diffusion. In particular, the majority of reactions happen via defect-cells SiO5 and OSi3. Moreover, the defect-cells do not uniformly distribute in the liquid, but they have a tendency to locate nearby forming large cluster. Further, it is revealed that the spatial distribution of reactions is heterogeneous. We found two distinct clusters. First cluster (none-reaction cluster) consists of particles on which no reaction happens. The second cluster (reaction cluster) includes particles where the reactions happen. The size of clusters found is dependent with temperature and diffusion time. Moreover, the mobility of particles in none-reaction cluster is significantly smaller than in reaction cluster. This indicates the dynamics heterogeneity in the liquid. We suggest that the dynamics slowdown is originated from the percolation of none-reaction cluster.