Investigating the Pressure-Induced Amorphization of Zeolitic Imidazolate Framework ZIF-8: Mechanical Instability Due to Shear Mode Softening
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- 作者：Aur茅lie U. Ortiz ; Anne Boutin ; Alain H. Fuchs ; Fran莽ois-Xavier Coudert
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2013
- 出版时间：June 6, 2013
- 年：2013
- 卷：4
- 期：11
- 页码：1861-1865
- 全文大小：271K
- 年卷期：v.4,no.11(June 6, 2013)
- ISSN：1948-7185
文摘
We provide the first molecular dynamics study of the mechanical instability that is the cause of pressure-induced amorphization of zeolitic imidazolate framework ZIF-8. By measuring the elastic constants of ZIF-8 up to the amorphization pressure, we show that the crystal-to-amorphous transition is triggered by the mechanical instability of ZIF-8 under compression, due to shear mode softening of the material. No similar softening was observed under temperature increase, explaining the absence of temperature-induced amorphization in ZIF-8. We also demonstrate the large impact of the presence of adsorbate in the pores on the mechanical stability and compressibility of the framework, increasing its shear stability. This first molecular dynamics study of ZIF mechanical properties under variations of pressure, temperature, and pore filling opens the way to a more comprehensive understanding of their mechanical stability, structural transitions, and amorphization.