Quasi-elastic neutron scattering and molecular dynamics simulation as complementary techniques for studying diffusion in zeolites

“…Our account has been adapted from ref. [15][16][17]. These references also give details of how to characterise localised motions of molecules such as rotation, which are outside the scope of the present article.…”

Section: Quasielastic Neutron Scattering: Molecular Mobility In Catalmentioning

confidence: 99%

“…15,21 However the scarcity of instruments available means that very few studies in catalytic systems are available in the literature. [22][23][24] The velocities of polarized neutrons are compared before and after the scattering event, using the Larmor precession of the neutron spin.…”

Section: Neutron Spin-echo Techniquesmentioning

confidence: 99%

Neutron spectroscopy as a tool in catalytic science

2017

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Catalytic science currently has access to a range of advanced experimental methods for the study of molecular behaviour in chemical processes. Neutron spectroscopy, however, is uniquely placed to gain detailed insight into such systems, particularly through techniques such as vibrational spectroscopy with neutrons (INS) which gives access to vibrational modes unavailable to conventional spectroscopy techniques, and quasielastic neutron scattering (QENS) which studies molecular motion on a range of timescales. The present article illustrates the role of these techniques in advancing the field of catalysis. We first provide a brief introduction to the basic principles of the techniques, and then discuss their use in the study of three key catalytic systems: the behaviour of hydrocarbons confined in zeolite catalysts; the methanol-to-hydrocarbons process; and methane reforming. We demonstrate the importance of neutron spectroscopy in understanding established catalytic processes, but also consider its role in the design of future catalytic systems.

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“…When cleverly used, Monte Carlo and molecular or Brownian dynamics simulations of model systems, for example, have yielded tremendous insights into the structure and relaxation modes of polymeric materials, 2 nanocomposites, 3,4 confined macromolecules, 5,6 liquid crystals, 7 biological membranes, 8 and biological macromolecules. 9 These simulations provide a window into the transport of molecules through porous materials such as zeolites, 10,11 and into the short-and intermediatetime relaxation modes of model glassformers 12 and colloidal and polymeric gels. [13][14][15] Multiscale modeling is, without a doubt, a particularly vibrant field of research where the engineering disciplines, the physical sciences, and the life sciences converge.…”

Section: In This Issuementioning

confidence: 99%

“…Interpretation of their experimental data requires molecular and multiscale models, and modeling is benefiting from a direct, unambiguous connection to experiment. 4,5,11,12 It is a field where much has been learned, but enormous, exciting challenges remain. …”

Section: In This Issuementioning

confidence: 99%

Multiscale Modeling in Advanced Materials Research: Challenges, Novel Methods, and Emerging Applications

Pablo¹,

Curtin²

2007

MRS Bull.

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The concept of multiscale modeling embodies the idea that a comprehensive description of a material will require an understanding over multiple time and length scales. A multiscale model requires that descriptions at all levels be consistent with each other, which can be particularly demanding for advanced materials and complex fluids. For crystalline materials, emerging modeling approaches have married smalland intermediate-scale descriptions in a highly effective manner, but challenges remain at long time and length scales. For soft materials, such as polymers or liquid crystals, modeling techniques have adopted a more or less systematic coarse-graining approach, in which atomic and molecular details are gradually blurred as one seeks to describe longer length scales. This approach presents its own brand of challenges. And, in spite of rapid advances, entire classes of materials, including amorphous glasses, foams, and gels, have resisted attempts to describe their structure and dynamics over long and relevant length and time scales. This issue of MRS Bulletin covers some areas of materials modeling in which enormous advances have been made, but which continue to raise intriguing questions and formidable challenges.wind of activity in the area of multiscale modeling and to scientific advances that even for the expert have been difficult to digest. For hard materials, available methods have matured to the point where increasingly comprehensive calculations can be performed to address subtle questions about relations between chemistry, structure, and material behavior. But among all the excitement, entire classes of materials have resisted attempts by modelers to reveal their secrets. In the particular case of soft materials (e.g., polymeric glasses and melts, biological macromolecules), widely used modeling approaches require enormous leaps of faith, and well-founded theoretical frameworks for the development of multiscale modeling strategies are only now beginning to emerge.For this issue of MRS Bulletin, we have identified five areas of materials modeling in which enormous advances have been made but which continue to raise intriguing questions and formidable challenges. These five areas are by no means comprehensive, and they represent only a thin slice of the materials modeling community. They do provide, however, a relatively broad overview of current thinking and emerging trends, and they offer a perspective on some of the developments that we might expect over the next decade.The methodology to be used for a particular problem depends on the length and time scales of interest (Figure 1). The concept of multiscale modeling embodies the idea that a comprehensive description of a material will require an understanding over multiple length and time scales. More subtle is the fact that a comprehensive, multiscale model requires that descriptions at all levels be consistent with each other. That requirement for consistency often demands that models for different processes or pieces of a problem be coup...

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Quasi-elastic neutron scattering and molecular dynamics simulation as complementary techniques for studying diffusion in zeolites

Cited by 262 publications

References 64 publications

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

Molecular Simulations of Zeolites: Adsorption, Diffusion, and Shape Selectivity

Neutron spectroscopy as a tool in catalytic science

Multiscale Modeling in Advanced Materials Research: Challenges, Novel Methods, and Emerging Applications

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