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 classi cal molecular dynamics calculations. Features qualitatively similar to thos e of fragile glasses are recovered at high temperatures. In particular, an intrinsic characteristic temperature T-c similar or equal to 3500 K is evid enced, above which the system starts to investigate nonharmonic potential e nergy basins. It is shown that the anharmonicities are essentially characte rized by a roughness appearing in the potential energy valleys explored by the system for temperatures above T-c.