scholarly journals Molecular Dynamics Simulations of CO2Molecules in ZIF-11 Using Refined AMBER Force Field

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
W. Wongsinlatam ◽  
T. Remsungnen

Nonbonding parameters of AMBER force field have been refined based onab initiobinding energies of CO2–[C7H5N2]−complexes. The energy and geometry scaling factors are obtained to be 1.2 and 0.9 forεandσparameters, respectively. Molecular dynamics simulations of CO2molecules in rigid framework ZIF-11, have then been performed using original AMBER parameters (SIM I) and refined parameters (SIM II), respectively. The site-site radial distribution functions and the molecular distribution plots simulations indicate that all hydrogen atoms are favored binding site of CO2molecules. One slight but notable difference is that CO2molecules are mostly located around and closer to hydrogen atom of imidazolate ring in SIM II than those found in SIM I. The Zn-Zn and Zn-N RDFs in free flexible framework simulation (SIM III) show validity of adapting AMBER bonding parameters. Due to the limitations of computing resources and times in this study, the results of flexible framework simulation using refined nonbonding AMBER parameters (SIM IV) are not much different from those obtained in SIM II.

Data in Brief ◽  
2016 ◽  
Vol 8 ◽  
pp. 1209-1214 ◽  
Author(s):  
Longhua Yang ◽  
Åge A. Skjevik ◽  
Wen-Ge Han Du ◽  
Louis Noodleman ◽  
Ross C. Walker ◽  
...  

2013 ◽  
Vol 91 (7) ◽  
pp. 552-558 ◽  
Author(s):  
Saleh Riahi ◽  
Benoît Roux ◽  
Christopher N. Rowley

The hydration of Mg2+ and Zn2+ is examined using molecular dynamics simulations using 3 computational approaches of increasing complexity: the CHARMM nonpolarizable force field based on the TIP3P water model, the Drude polarizable force field based on the SWM4-NDP water model, and a combined QM/MM approach in which the inner coordination sphere is represented using a high-quality density functional theory (DFT) model (PBE/def2-TZVPP), and the remainder of the bulk water solvent is represented using the polarizable SWM4-NDP water model. The characteristic structural distribution functions (radial, angular, and tilt) are comparedand show very good agreement between the polarizable force field and QM/MM approaches. They predict an average Mg–O distance of 2.11 Å and an Zn–O distance of 2.13 Å, in good agreement with the available experimental neutron scattering and EXAFS data, while the Mg–O distances calculated using the nonpolarizable force field are 0.1 Å too short. Mg2+ (aq) and Zn2+ (aq) both have a coordination number of 6 and have a remarkably similar octahedral coordination mode, despite the chemical differences between these ions. Thermodynamic integration was used to calculate the relative hydration free energies of these ions (ΔΔGhydr). The nonpolarizable model is in error by 60 kcal mol– 1 and incorrectly predicts that Mg2+ has the more negative hydration energy. The Drude polarizable model predicts a ΔΔGhydr of only –13.2 kcal kcal mol– 1, an improvement over the results of the nonpolarizable force field, but still signficantly different than the experimental value of –30.1 kcal mol–1. The combined QM/MM approach performs much better, predicting a ΔΔGhydr of –34.8 kcal mol–1 in excellent agreement with experiment. These calculations support the experimental observation that Zn2+ has more favourable solvation free energy than Mg2+ despite having a very similar solvation structure.


Data in Brief ◽  
2021 ◽  
Vol 38 ◽  
pp. 107401
Author(s):  
Surl-Hee Ahn ◽  
Christian Seitz ◽  
Vinícius Wilian D. Cruzeiro ◽  
J. Andrew McCammon ◽  
Andreas W. Götz

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Miraslau L. Barabash ◽  
William A. T. Gibby ◽  
Carlo Guardiani ◽  
Alex Smolyanitsky ◽  
Dmitry G. Luchinsky ◽  
...  

AbstractIn order to permeate a nanopore, an ion must overcome a dehydration energy barrier caused by the redistribution of surrounding water molecules. The redistribution is inhomogeneous, anisotropic and strongly position-dependent, resulting in complex patterns that are routinely observed in molecular dynamics simulations. Here, we study the physical origin of these patterns and of how they can be predicted and controlled. We introduce an analytic model able to predict the patterns in a graphene nanopore in terms of experimentally accessible radial distribution functions, giving results that agree well with molecular dynamics simulations. The patterns are attributable to a complex interplay of ionic hydration shells with water layers adjacent to the graphene membrane and with the hydration cloud of the nanopore rim atoms, and we discuss ways of controlling them. Our findings pave the way to designing required transport properties into nanoionic devices by optimising the structure of the hydration patterns.


RSC Advances ◽  
2014 ◽  
Vol 4 (89) ◽  
pp. 48621-48631 ◽  
Author(s):  
Eleanor R. Turpin ◽  
Sam Mulholland ◽  
Andrew M. Teale ◽  
Boyan B. Bonev ◽  
Jonathan D. Hirst

2002 ◽  
Vol 580 (1-3) ◽  
pp. 33-38
Author(s):  
Cristina P. Gonçalves ◽  
Flávia Rolim ◽  
Vinı́cius C. Mota ◽  
José R. Mohallem

1995 ◽  
Vol 396 ◽  
Author(s):  
M. tang ◽  
L. colombo ◽  
T. Diaz De La Rubia

AbstractTight-binding molecular dynamics (TBMD) simulations are performed (i) to evaluate the formation and binding energies of point defects and defect clusters, (ii) to compute the diffusivity of self-interstitial and vacancy in crystalline silicon, and (iii) to characterize the diffusion path and mechanism at the atomistic level. In addition, the interaction between individual defects and their clustering is investigated.


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