TY  - JOUR
AU  - Liu, Maoyuan
AU  - Jacob, Aurélie
AU  - Schmetterer, Clemens
AU  - Masset, Patrick J
AU  - Hennet, Louis
AU  - Fischer, Henry E
AU  - Kozaily, Jad
AU  - Jahn, Sandro
AU  - Gray-Weale, Angus
TI  - From Atomic Structure to Excess Entropy: A Neutron Diffraction and Density Functional Theory Study of CaO−Al$_{2}$ O$_{3}$ −SiO$_{2}$ Melts
JO  - Journal of physics / Condensed matter
VL  - 28
IS  - 13
SN  - 1361-648X
CY  - Bristol
PB  - IOP Publ.
M1  - FZJ-2016-02301
SP  - 135102
PY  - 2016
AB  - Calcium aluminosilicate $\text{CaO}-\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}-\text{Si}{{\text{O}}_{2}}$ (CAS) melts with compositions ${{\left(\text{CaO}-\text{Si}{{\text{O}}_{2}}\right)}_{x}}{{\left(\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}\right)}_{1-x}}$ for x  <  0.5 and ${{\left(\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}\right)}_{x}}{{\left(\text{Si}{{\text{O}}_{2}}\right)}_{1-x}}$ for $x\geqslant 0.5$ are studied using neutron diffraction with aerodynamic levitation and density functional theory molecular dynamics modelling. Simulated structure factors are found to be in good agreement with experimental structure factors. Local atomic structures from simulations reveal the role of calcium cations as a network modifier, and aluminium cations as a non-tetrahedral network former. Distributions of tetrahedral order show that an increasing concentration of the network former Al increases entropy, while an increasing concentration of the network modifier Ca decreases entropy. This trend is opposite to the conventional understanding that increasing amounts of network former should increase order in the network liquid, and so decrease entropy. The two-body correlation entropy S 2 is found to not correlate with the excess entropy values obtained from thermochemical databases, while entropies including higher-order correlations such as tetrahedral order, O–M–O or M–O–M bond angles and Q N environments show a clear linear correlation between computed entropy and database excess entropy. The possible relationship between atomic structures and excess entropy is discussed.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000371905200016
DO  - DOI:10.1088/0953-8984/28/13/135102
UR  - https://juser.fz-juelich.de/record/808668
ER  -