THE FIRST SHARP DIFFRACTION PEAK IN GLASSES AND IN OTHER AMORPHOUS SUBSTANCES

It is shown that there exists a numerical relationship between the position of the first sharp diffraction peak, Q(1), and the first interatomic distance, r(1), which obeys a simple equation d = ar(1) + b where d = 2 pi/Q(1) is the equivalent distance and the coefficients (a, b) specify the group of amorphous substances-glasses, amorphous metals and semiconductors. liquids of a definite nature. The scale of medium-range order xi = d/r(1) is introduced aod it is proposed that the xi-r(1) plot could be used for classification of amorphous structures.