Computer Investigation of the Energy Landscape of Amorphous Silica

The multidimensional topography of the collective potential energy function of a so-called strong glass former (silica) is analyzed by means of classical molecular dynamics calculations. Features qualitatively similar to those of fragile glasses are recovered at high temperatures. In particular, an intrinsic characteristic temperature $T_c\simeq 3500\mathrm{K}$ is evidenced, above which the system starts to investigate nonharmonic potential energy basins. It is shown that the anharmonicities are essentially characterized by a roughness appearing in the potential energy valleys explored by the system for temperatures above $T_c$.