TY - JOUR
T1 - Molecular understanding of dynamical properties of the vapor/ethanol- aqueous-solution interface
AU - Andoh, Y.
AU - Yasuoka, K.
N1 - Funding Information:
This research is supported by the Core Research for Evolution Science and Technology (CREST) of the Japan Science and Technology Corporation (JST). This research is supported in part by Grant in Aid for the 21st century center of excellence (COE) for “System Design: Paradigm Shift from Intelligence to Life” from Ministry of Education, Culture, Sport and Technology in Japan.
PY - 2007/1
Y1 - 2007/1
N2 - The variation of dynamical properties of the vapor/ethanol-aqueous-solution interface with excess adsorption of ethanol is investigated by a molecular dynamics (MD) simulation. Five independent NVT (T=298.15K) constant MD runs were performed, where a slab of ethanol-aqueous-solution with ethanol mole fraction [image omitted] of 0.0052, 0.012, 0.024, 0.057 and 0.12, respectively, reached an equilibrium state of adsorption. The positional dependence of molecular self-diffusivity was evaluated by profiles of the self-diffusion coefficient of ethanol and water along the axis normal to the interface. The profile of the ethanol self-diffusion coefficient showed local extrema at the interface, the degree of which is weakened with increase of [image omitted]. Lateral self-diffusivity of an adsorbed ethanol molecule was also evaluated by the two-dimensional (2D) self-diffusion coefficient at the interface, which is a monotonically decreasing function of ethanol excess adsorption. Moreover, the desorption probability of an adsorbed ethanol molecule was estimated, which monotonically increases with ethanol excess adsorption. The molecular origin of the variation of these dynamical properties was explained by correlating them with the profile of the free energy change.
AB - The variation of dynamical properties of the vapor/ethanol-aqueous-solution interface with excess adsorption of ethanol is investigated by a molecular dynamics (MD) simulation. Five independent NVT (T=298.15K) constant MD runs were performed, where a slab of ethanol-aqueous-solution with ethanol mole fraction [image omitted] of 0.0052, 0.012, 0.024, 0.057 and 0.12, respectively, reached an equilibrium state of adsorption. The positional dependence of molecular self-diffusivity was evaluated by profiles of the self-diffusion coefficient of ethanol and water along the axis normal to the interface. The profile of the ethanol self-diffusion coefficient showed local extrema at the interface, the degree of which is weakened with increase of [image omitted]. Lateral self-diffusivity of an adsorbed ethanol molecule was also evaluated by the two-dimensional (2D) self-diffusion coefficient at the interface, which is a monotonically decreasing function of ethanol excess adsorption. Moreover, the desorption probability of an adsorbed ethanol molecule was estimated, which monotonically increases with ethanol excess adsorption. The molecular origin of the variation of these dynamical properties was explained by correlating them with the profile of the free energy change.
KW - Anisotropy
KW - Desorption probability
KW - Ethanol aqueous solution
KW - Free energy profile
KW - Monolayer
KW - Self-diffusion coefficient
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U2 - 10.1080/08927020601075337
DO - 10.1080/08927020601075337
M3 - Article
AN - SCOPUS:33947419710
VL - 33
SP - 139
EP - 145
JO - Molecular Simulation
JF - Molecular Simulation
SN - 0892-7022
IS - 1-2
ER -