TY - JOUR
T1 - Structure, dynamics, and thermodynamics of a family of potentials with tunable softness
AU - Shi, Zane
AU - Debenedetti, Pablo G.
AU - Stillinger, Frank H.
AU - Ginart, Paul
N1 - Funding Information:
P.G.D. gratefully acknowledges the support of the Princeton Center for Complex Materials (National Science Foundation Materials Research Science and Engineering Center Grant No. DMR-0819860) and of the National Science Foundation (NSF) (Grant No. CHE-0908265).
PY - 2011/8/28
Y1 - 2011/8/28
N2 - We investigate numerically the structure, thermodynamics, and relaxation behavior of a family of (n, 6) Lennard-Jones-like glass-forming binary mixtures interacting via pair potentials with variable softness, fixed well depth, and fixed well depth location. These constraints give rise to progressively more negative attractive tails upon softening, for separations greater than the potential energy minimum. Over the range of conditions examined, we find only modest dependence of structure on softness. In contrast, decreasing the repulsive exponent from n = 12 to n = 7 causes the diffusivity to increase by as much as two orders of magnitude at fixed temperature and density, and produces mechanically stable packings (inherent structures) with cohesive energies that are, on average, ∼1.7 well depths per particle larger than for the corresponding Lennard-Jones (n = 12) case. The softer liquids have markedly higher entropies and lower Kauzmann temperatures than their Lennard-Jones (n = 12) counterparts, and they remain diffusive down to appreciably lower temperatures. We find that softening leads to a modest increase in fragility.
AB - We investigate numerically the structure, thermodynamics, and relaxation behavior of a family of (n, 6) Lennard-Jones-like glass-forming binary mixtures interacting via pair potentials with variable softness, fixed well depth, and fixed well depth location. These constraints give rise to progressively more negative attractive tails upon softening, for separations greater than the potential energy minimum. Over the range of conditions examined, we find only modest dependence of structure on softness. In contrast, decreasing the repulsive exponent from n = 12 to n = 7 causes the diffusivity to increase by as much as two orders of magnitude at fixed temperature and density, and produces mechanically stable packings (inherent structures) with cohesive energies that are, on average, ∼1.7 well depths per particle larger than for the corresponding Lennard-Jones (n = 12) case. The softer liquids have markedly higher entropies and lower Kauzmann temperatures than their Lennard-Jones (n = 12) counterparts, and they remain diffusive down to appreciably lower temperatures. We find that softening leads to a modest increase in fragility.
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U2 - 10.1063/1.3627148
DO - 10.1063/1.3627148
M3 - Article
C2 - 21895205
AN - SCOPUS:80052404399
SN - 0021-9606
VL - 135
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 8
M1 - 084513
ER -