Advanced search
2 files | 7.19 MB Add to list

Mechanical properties from periodic plane wave quantum mechanical codes: the challenge of the flexible nanoporous MIL-47(V) framework

Danny Vanpoucke (UGent) , Kurt Lejaeghere (UGent) , Veronique Van Speybroeck (UGent) , Michel Waroquier (UGent) and An Ghysels (UGent)
(2015) JOURNAL OF PHYSICAL CHEMISTRY C. 119(41). p.23752-23766
Author
Organization
Abstract
Modeling the flexibility of metal organic frameworks (MOFs) requires the computation of mechanical properties from first principles, e.g., for screening of materials in a database, for gaining insight into structural transformations, and for force field development. However, this paper shows that computations with periodic density functional theory are challenged by the flexibility of these materials: guidelines from experience with standard solid-state calculations cannot be simply transferred to flexible porous frameworks. Our test case, the MIL-47(V) material, has a large-pore and a narrow-pore shape. The effect of Pulay stress (cf. Pulay forces) leads to drastic errors for a simple structure optimization of the flexible MIL-47(V) material. Pulay stress is an artificial stress that tends to lower the volume and is caused by the finite size of the plane wave basis set. We have investigated the importance of this Pulay stress, of symmetry breaking, and of k-point sampling on (a) the structure optimization and (b) mechanical properties such as elastic constants and bulk modulus, of both the large-pore and narrow-pore structure of MIL-47(V). We found that, in the structure optimization, Pulay effects should be avoided by using a fitting procedure, in which an equation of state E(V)(EOS) is fit to a series of energy versus volume points. Manual symmetry breaking could successfully lower the energy of MIL-47(V) by distorting the vanadium oxide distances in the vanadyl chains and by rotating the benzene linkers. For the mechanical properties, the curvature of the EOS curve was compared with the Reuss bulk modulus, derived from the elastic tensor in the harmonic approximation. Errors induced by anharmonicity, the eggbox effect, and Pulay effects propagate into the Reuss modulus. The strong coupling of the unit cell axes when the unit cell deforms expresses itself in numerical instability of the Reuss modulus. For a flexible material, it is therefore advisible to resort to the EOS fit procedure.
Keywords
NORMAL-MODE ANALYSIS, STRUCTURAL TRANSITION, METAL-ORGANIC-FRAMEWORK, ADSORPTION PROPERTIES, NEUTRON-SCATTERING, GAS-ADSORPTION, CO2 ADSORPTION, MIL-53, STATE, FLEXIBILITY

Downloads

  • (...).pdf
    • full text
    • |
    • UGent only
    • |
    • PDF
    • |
    • 3.47 MB
  • 15-JPhysChemC-final-draft-Vanpoucke.pdf
    • full text
    • |
    • open access
    • |
    • PDF
    • |
    • 3.72 MB

Citation

Please use this url to cite or link to this publication:

MLA
Vanpoucke, Danny et al. “Mechanical Properties from Periodic Plane Wave Quantum Mechanical Codes: The Challenge of the Flexible Nanoporous MIL-47(V) Framework.” JOURNAL OF PHYSICAL CHEMISTRY C 119.41 (2015): 23752–23766. Print.
APA
Vanpoucke, D., Lejaeghere, K., Van Speybroeck, V., Waroquier, M., & Ghysels, A. (2015). Mechanical properties from periodic plane wave quantum mechanical codes: the challenge of the flexible nanoporous MIL-47(V) framework. JOURNAL OF PHYSICAL CHEMISTRY C, 119(41), 23752–23766.
Chicago author-date
Vanpoucke, Danny, Kurt Lejaeghere, Veronique Van Speybroeck, Michel Waroquier, and An Ghysels. 2015. “Mechanical Properties from Periodic Plane Wave Quantum Mechanical Codes: The Challenge of the Flexible Nanoporous MIL-47(V) Framework.” Journal of Physical Chemistry C 119 (41): 23752–23766.
Chicago author-date (all authors)
Vanpoucke, Danny, Kurt Lejaeghere, Veronique Van Speybroeck, Michel Waroquier, and An Ghysels. 2015. “Mechanical Properties from Periodic Plane Wave Quantum Mechanical Codes: The Challenge of the Flexible Nanoporous MIL-47(V) Framework.” Journal of Physical Chemistry C 119 (41): 23752–23766.
Vancouver
1.
Vanpoucke D, Lejaeghere K, Van Speybroeck V, Waroquier M, Ghysels A. Mechanical properties from periodic plane wave quantum mechanical codes: the challenge of the flexible nanoporous MIL-47(V) framework. JOURNAL OF PHYSICAL CHEMISTRY C. 2015;119(41):23752–66.
IEEE
[1]
D. Vanpoucke, K. Lejaeghere, V. Van Speybroeck, M. Waroquier, and A. Ghysels, “Mechanical properties from periodic plane wave quantum mechanical codes: the challenge of the flexible nanoporous MIL-47(V) framework,” JOURNAL OF PHYSICAL CHEMISTRY C, vol. 119, no. 41, pp. 23752–23766, 2015.
@article{6977097,
  abstract     = {Modeling the flexibility of metal organic frameworks (MOFs) requires the computation of mechanical properties from first principles, e.g., for screening of materials in a database, for gaining insight into structural transformations, and for force field development. However, this paper shows that computations with periodic density functional theory are challenged by the flexibility of these materials: guidelines from experience with standard solid-state calculations cannot be simply transferred to flexible porous frameworks. Our test case, the MIL-47(V) material, has a large-pore and a narrow-pore shape. The effect of Pulay stress (cf. Pulay forces) leads to drastic errors for a simple structure optimization of the flexible MIL-47(V) material. Pulay stress is an artificial stress that tends to lower the volume and is caused by the finite size of the plane wave basis set. We have investigated the importance of this Pulay stress, of symmetry breaking, and of k-point sampling on (a) the structure optimization and (b) mechanical properties such as elastic constants and bulk modulus, of both the large-pore and narrow-pore structure of MIL-47(V). We found that, in the structure optimization, Pulay effects should be avoided by using a fitting procedure, in which an equation of state E(V)(EOS) is fit to a series of energy versus volume points. Manual symmetry breaking could successfully lower the energy of MIL-47(V) by distorting the vanadium oxide distances in the vanadyl chains and by rotating the benzene linkers. For the mechanical properties, the curvature of the EOS curve was compared with the Reuss bulk modulus, derived from the elastic tensor in the harmonic approximation. Errors induced by anharmonicity, the eggbox effect, and Pulay effects propagate into the Reuss modulus. The strong coupling of the unit cell axes when the unit cell deforms expresses itself in numerical instability of the Reuss modulus. For a flexible material, it is therefore advisible to resort to the EOS fit procedure.},
  author       = {Vanpoucke, Danny and Lejaeghere, Kurt and Van Speybroeck, Veronique and Waroquier, Michel and Ghysels, An},
  issn         = {1932-7447},
  journal      = {JOURNAL OF PHYSICAL CHEMISTRY C},
  keywords     = {NORMAL-MODE ANALYSIS,STRUCTURAL TRANSITION,METAL-ORGANIC-FRAMEWORK,ADSORPTION PROPERTIES,NEUTRON-SCATTERING,GAS-ADSORPTION,CO2 ADSORPTION,MIL-53,STATE,FLEXIBILITY},
  language     = {eng},
  number       = {41},
  pages        = {23752--23766},
  title        = {Mechanical properties from periodic plane wave quantum mechanical codes: the challenge of the flexible nanoporous MIL-47(V) framework},
  url          = {http://dx.doi.org/10.1021/acs.jpcc.5b06809},
  volume       = {119},
  year         = {2015},
}

Altmetric
View in Altmetric
Web of Science
Times cited: