Univ Wales, Dept Phys, Aberystwyth SY23 3BZ, Dyfed, Wales
; Univ Kent, Phys & Chem Labs, Canterbury CT2 7NR, Kent, England
; Acad Sinica, Inst High Energy Phys, Beijing Synchrotron Radiat Facil, Beijing 100039, Peoples R China
Article; Proceedings Paper
Alkali X-ray absorption fine structure (XAFS) spectra from KxCs(1-x)Si2O5 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. (C) 1998 Elsevier Science B.V. All rights reserved.