RESULTS

 

Three examples are presented :
glassy SiO2, ZnCl2 and NaPbM2F9 (M = Fe, V).

Coordinations were constrained :
SiO4 and ZnCl4 tetrahedra ; MF6 octahedra

So that the final RMC models keep essentially the crystal structure features of the RDM starting models, being the phases in which devitrify the glasses, in all cases.






Conditions for building the RMC models
from the RDM ones


 
ZnCl2
SiO2
NaPbM2F9
Initial RDM model
d -ZnCl2
carnegieite
NaPbFe2F9
Axes enlarged
ax6, bx4, cx6
ax4, bx4, cx4
ax3, bx2, cx3
Total atom number in RMC modelling
1728
1536
936
RMC constraints
[ZnCl4]
[SiO4]
[MF6]

 
 


 
 

Final reliabilities Rp (%).
N = neutron, X = X-ray ; M = Fe, V.


 
ZnCl2
SiO2
NaPbM2F9
RDM
2.40 (N)
2.45 (N)
2.37 (X)
2.00 (N, Fe)
2.45 (N, V)
5.07 (X, Fe)
RMC - random
0.76 (N)
unavailable
D.A. Keen & R.L. McGreevy
Nature 344 (1990) 423.
0.77 (N, Fe)
1.00 (N, V)
1.14 (X, Fe)
RMC from RDM
starting models 
1.09 (N)
1.48 (N)
2.00 (N)
0.81 (N, Fe)
1.22 (N, V)
1.75 (X, Fe)