Clustering and percolation in lithium borate glasses.
Molecular dynamics simulations are carried out in xLi2O-(1-x)B2O3 glasses (x=0.2-0.6) at T=1250 K, where cluster size distributions for Li cations and nonbridging oxygen (NBO) atoms are calculated. The existence of percolating clusters above x=0.3 places the percolation threshold between x=0.3 and 0.4 for the system under investigation, which is consistent with the abrupt increase of the diffusion coefficient of Li cations observed at x=0.4. It is also shown that the clusters of Li cations consist mainly of Li atoms found in the vicinity of NBO atoms. This result explains the higher mobility exhibited by this type of cations compared to the mobility of Li cations in the vicinity of bridging oxygen atoms.
Vegiri
Alice
A
Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vas. Constantinou Ave., 11635 Athens, Greece. avegiri@eie.gr
Varsamis
Cristos-Platon E
CP