A Molecular Dynamics investigation of the influence of framework flexibility on self-diffusivity of ethane in Zn(tbip) frameworks

作者：Seehamart K; Nanok T; Krishna R; van Baten J M; Remsungnen T; Fritzsche S^*

来源：Microporous and Mesoporous Materials, 2009, 125(1-2): 97-100.

DOI：10.1016/j.micromeso.2009.01.020

• Self-diffusivity
• Adsorption
• Molecular Dynamics
• Configurational-Bias Monte Carlo
• Thermodynamic factor
• Framework flexibility
• Isotherm inflection
• Ethane
• Metal-organic frameworks

Configurational-Bias Monte Carlo simulations of the adsorption isotherm of ethane in Zn(tbip) (H(2)tbip = 5-tert-butyl isophthalic acid), a representative of metal-organic frameworks, show an inflection at a loading, q(i) = 6 molecules per unit cell. This inflection causes the inverse thermodynamic factor, 1/Gamma(i), to display a minimum at q(i) = 6, along with a maximum at q(i) approximate to 10. Molecular Dynamics (MD) simulations of the self-diffusivity D(i,self), taking account of the framework flexibility of Zn(tbip) show that the D(i,self) - q(i) dependence follows that of 1/Gamma(i) - q(i), with a minimum at q(i) = 6. Remarkably, MD simulations assuming a rigid framework yield significantly lower values of the self-diffusivities, and show a monotonic decrease of D(i,self) with q(i).

• 出版日期2009-10-1