Modeling GeAsSe, Glasses

One such application of these ideas is via the use of the RMC method in the generation of the starting structure for subsequent DFT MD simulations. As outlined earlier, RMC simulations can have a variety of experimental inputs and experimentally motivated constraints. Here we outline an application employing EXAFS experimental data along with some constraints upon the system coordination. 

The EXAFS signal is derived from the X-ray absorption coefficient fL E], which is measured for a material as a function of the incident X-ray energy. The coefficient simply relates the intensity of the incident X-rays to the intensity of the transmitted X-rays at a given incident energy. A typical spectrum shows an initial maximum 

Within the RMC code, the calculated EXAFS signal for a particular element Z from the simulation atomic coordinates is given by 

RMC(EXAPS+COORD + ANGLE) RMC (EXAPS+COORD + ANCLE)  

Bonding structural units in isocoordinate GeAsSe glasses of increasing Ge and Se concentration. 

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Opletal G., Wang R. P. and Russo S. R, Investigation of bonding within ab-initio models of GeAsSe glasses, Chem. Phys. Lett., 575, 97-100 (2013). 

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