Changing Debye–Waller factors in mixed alkali K xCs (1− x) Si 2O 5 glasses

Abstract

Alkali X-ray absorption fine structure (XAFS) spectra from K x Cs (1− x) Si 2O 5 glasses measured at room temperature reveal changes in the Debye–Waller factors of nearest neighbour oxygen shells as the mixed alkali composition is altered. The thermal contributions have been estimated using the correlated Einstein model from the different frequencies of the alkali vibrations in the far infrared. By comparing these with the changing Debye–Waller factors measured from XAFS, the contribution due to modifications in structural disorder around each of the alkalis is assessed.