Change in the topology of the glass forming liquid GeSe<sub>2</sub> with increasing temperature
Ingrid Petri; Philip S Salmon; W Spencer Howells
Журнал:
Journal of Physics: Condensed Matter
Дата:
1999-12-20
Аннотация:
The change in topology with increasing temperature of liquid GeSe<sub>2</sub> was studied by using neutron diffraction to measure the Bhatia-Thornton number-number partial structure factor, S<sub>NN</sub>(Q), where Q is the scattering vector. As the temperature is raised from 800 to 1100 °C there is a broadening but little other change in the peaks describing the local coordination environment. There is, however, a collapse of the intermediate range atomic ordering of the network associated with the Ge-Ge correlations as manifest by a substantial reduction in the height of the first sharp diffraction peak and a shift in its position from 0.99(1) to 1.05(1) Å<sup>-1</sup>. The changes in the structure with increasing temperature mimic those observed as the composition of liquid GeSe<sub>2</sub> is changed to the GeSe stoichiometry by the addition of germanium. The significance of the results for recent Car-Parinello type ab-initio molecular dynamics simulations is briefly discussed.
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