scholarly journals Methanol diffusion in zeolite HY: a combined quasielastic neutron scattering and molecular dynamics simulation study

2016 ◽  
Vol 18 (26) ◽  
pp. 17294-17302 ◽  
Author(s):  
Alexander J. O'Malley ◽  
Victoria García Sakai ◽  
Ian P. Silverwood ◽  
Nikolaos Dimitratos ◽  
Stewart F. Parker ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Neutron Scattering ◽  
Simulation Study ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering

The diffusion of methanol in zeolite HY is studied using tandem quasielastic neutron scattering (QENS) experiments and molecular dynamics (MD) simulations at 300–400 K.

scholarly journals Molecular behaviour of phenol in zeolite Beta catalysts as a function of acid site presence: a quasielastic neutron scattering and molecular dynamics simulation study

2019 ◽  
Vol 9 (23) ◽  
pp. 6700-6713 ◽  
Author(s):  
Carlos Hernandez-Tamargo ◽  
Alexander O'Malley ◽  
Ian P. Silverwood ◽  
Nora H. de Leeuw
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Simulation Study ◽  
Acid Site ◽  
Dynamic Behaviour ◽  
Acid Sites ◽  
Zeolite Beta ◽  
Dynamics Simulation ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering

The dynamic behaviour of phenol in zeolite Beta is strongly influenced by the presence of Brønsted acid sites.

scholarly journals Comparing ammonia diffusion in NH3-SCR zeolite catalysts: a quasielastic neutron scattering and molecular dynamics simulation study

2018 ◽  
Vol 20 (17) ◽  
pp. 11976-11986 ◽  
Author(s):  
A. J. O'Malley ◽  
M. Sarwar ◽  
J. Armstrong ◽  
C. R. A. Catlow ◽  
I. P. Silverwood ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Neutron Scattering ◽  
Zeolite Catalysts ◽  
Dynamics Simulation ◽  
Simulation Studies ◽  
Nh3 Scr ◽  
Small Pore ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering

Neutron scattering and simulation studies reveal important consistencies and differences in ammonia mobility in small pore NH3-SCR zeolite catalysts.

scholarly journals Quasielastic Neutron Scattering and Molecular Dynamics Simulation Study on the Molecular Behaviour of Catechol in Zeolite Beta

2020 ◽  
Author(s):  
Carlos Hernandez-Tamargo ◽  
Ian P. Silverwood ◽  
Alexander J. O’Malley ◽  
Nora H. de Leeuw
Keyword(s):  
Molecular Dynamics ◽  
Neutron Scattering ◽  
Md Simulations ◽  
Acid Sites ◽  
Zeolite Beta ◽  
Dynamics Simulation ◽  
Oh Groups ◽  
Quasielastic Neutron ◽  
Quasielastic Neutron Scattering ◽  
Dynamics Simulations

AbstractThe dynamics of catechol in zeolite Beta was studied using quesielastic neutron scattering (QENS) experiments and molecular dynamics simulations at 393 K, to understand the behaviour of phenolic monomers relevant in the catalytic conversion of lignin via metal nanoparticles supported on zeolites. Compared to previous work studying phenol, both methods observe that the presence of the second OH group in catechol can hinder mobility significantly, as explained by stronger hydrogen-bonding interactions between catechol and the Brønsted sites of the zeolite. The instrumental timescale of the QENS experiment allows us to probe rotational motion, and the catechol motions are best fit to an isotropic rotation model with a $$D^{rot}$$ D rot of 2.9 × 10$$^{10}$$ 10 s$$^{-1}$$ - 1 . While this $$D^{rot}$$ D rot is within error of that measured for phenol, the fraction of molecules immobile on the instrumental timescale is found to be significantly higher for catechol. The MD simulations also exhibit this increased in ‘immobility’, showing that the long-range translational diffusion coefficients of catechol are lower than phenol by a factor of 7 in acidic zeolite Beta, and a factor of $$\sim$$ ∼ 3 in the siliceous material, further illustrating the significance of Brønsted site H-bonding. Upon reproducing QENS observables from our simulations to probe rotational motions, a combination of two isotropic rotations was found to fit the MD-calculated EISF; one corresponds to the free rotation of catechol in the pore system of the zeolite, while the second rotation is used to approximate a restricted and rapid “rattling”, consistent with molecules anchored to the acid sites through their OH groups, the motion of which is too rapid to be observed by experiment.

scholarly journals Influence on ferric chloride aqueous solution caused by external electrostatic field: a molecular dynamics simulation study

RSC Advances ◽  
2018 ◽  
Vol 8 (68) ◽  
pp. 38706-38714 ◽  
Author(s):  
Shi Zhibo ◽  
Li Liyi ◽  
Han Yong ◽  
Bai Jie
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solution ◽  
Molecular Dynamics Simulation ◽  
Ferric Chloride ◽  
Electrostatic Field ◽  
Simulation Study ◽  
Dynamic Properties ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Electrostatic Fields

A detailed analysis of structural properties and dynamic properties of ferric chloride aqueous solution under external electrostatic fields with different intensities was performed by molecular dynamics (MD) simulations.

A Combined Experimental and Molecular Dynamics Simulation Study on the Miscibility of Eucommia Ulmoides Gum with Several Rubbers

2017 ◽  
Vol 25 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Fei-Zhou Li ◽  
Zhen-Lin Lu ◽  
Dong-Ping Tian
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Phase Diagrams ◽  
Interaction Parameter ◽  
Simulation Study ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Eucommia Ulmoides ◽  
Mixing Energy ◽  
Eucommia Ulmoides Gum

This paper analyzes the miscibility state of EUG blended with CR, BR, SBR, NR and NBR via Molecular Dynamics (MD) simulations performed using Blends and the Flory-Huggins interaction parameter, phase diagrams, and mixing energy. The results showed that EUG can be miscible with CR, BR, SBR, NR, and NBR above 350K, and the simulation predictions and experimental results were mainly the same.

Self Diffusion in Liquid Titanium: Quasielastic Neutron Scattering and Molecular Dynamics Simulation

2009 ◽  
Vol 289-292 ◽  
pp. 609-614 ◽  
Author(s):  
Andreas Meyer ◽  
Jürgen Horbach ◽  
O. Heinen ◽  
Dirk Holland-Moritz ◽  
T. Unruh
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Neutron Scattering ◽  
The Self ◽  
Dynamics Simulation ◽  
Self Diffusion ◽  
Quasielastic Neutron ◽  
Liquid Titanium ◽  
Quasielastic Neutron Scattering ◽  
Self Diffusion Coefficient

Self diffusion in liquid titanium was measured at 2000K by quasielastic neutron scattering (QNS) in combination with container less processing via electromagnetic levitation. At small wavenumbers q the quasielastic signal is dominated by incoherent scattering. Up to about 1.2 °A−1 the width of the quasielastic line exhibits a q2 dependence as expected for long range atomic transport, thus allowing to measure the self diffusion coefficient DTi. As a result the value DTi = (5.3± 0.2)× 10−9 m2s−1 was obtained.With a molecular dynamics (MD) computer simulation using an embedded atom model (EAM) for Ti, the self diffusion coefficient is determined from the mean square displacement as well as from the decay of the incoherent intermediate scattering function at different q. By comparing both methods, we show that the hydrodynamic prediction of a q2 dependence indeed extends up to about 1.2 °A−1. Since this result does not depend significantly on the details of the interatomic potential, our findings show that accurate values of self diffusion coefficients in liquid metals can be measured by QNS on an absolute scale.

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