scholarly journals Theoretical Investigation of the Fusion Process of Mono-Cages to Tri-Cages with CH4/C2H6 Guest Molecules in sI Hydrates

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7071
Author(s):  
Shuxian Wei ◽  
Siyuan Liu ◽  
Shoufu Cao ◽  
Sainan Zhou ◽  
Yong Chen ◽  
...  
Keyword(s):  
Natural Gas ◽  
Density Functional ◽  
Fusion Energy ◽  
Fusion Process ◽  
Large Cage ◽  
Cage Structure ◽  
Microscopic Mechanism ◽  
Functional Theory ◽  
Guest Molecules ◽  
Further Development

Owing to a stable and porous cage structure, natural gas hydrates can store abundant methane and serve as a potentially natural gas resource. However, the microscopic mechanism of how hydrate crystalline grows has not been fully explored, especially for the structure containing different guest molecules. Hence, we adopt density functional theory (DFT) to investigate the fusion process of structure I hydrates with CH4/C2H6 guest molecules from mono-cages to triple-cages. We find that the volume of guest molecules affects the stabilities of large (51262, L) and small (512, s) cages, which are prone to capture C2H6 and CH4, respectively. Mixed double cages (small cage and large cage) with the mixed guest molecules have the highest stability and fusion energy. The triangular triple cages exhibit superior stability because of the three shared faces, and the triangular mixed triple cages (large-small-large) structure with the mixed guest molecules shows the highest stability and fusion energy in the triple-cage fusion process. These results can provide theoretical insights into the growth mechanism of hydrates with other mono/mixed guest molecules for further development and application of these substances.

scholarly journals Supramolecular Complexes of Cucurbiturils with Second Group Metal Salts and Hydrates and Histamine

INEOS OPEN ◽  
2021 ◽  
Vol 4 ◽  
Author(s):  
Yu. A. Borisov ◽  
◽  
S. S. Kiselev ◽  
Keyword(s):  
Aqueous Solution ◽  
Density Functional Theory ◽  
Density Functional ◽  
Metal Salts ◽  
Supramolecular Complexes ◽  
Water Molecules ◽  
Functional Theory ◽  
Guest Molecules ◽  
First Time ◽  
Formation Energies

The interaction of cucurbiturils (Q6, Q7, and Q8) with Ca and Ba chlorides and iodides are studied for the first time by density functional theory. The thermodynamic parameters for the formation of host–guest complexes are calculated. The structures of complexes of Q6 and Q7 with one and two guest molecules are established. The energy parameters for the transfer of Be2+ and Ba2+ cations from an aqueous solution into the cavity of Q7 containing n water molecules are defined. The dependences of the formation energies for complexes Q7WnBe2+ and Q7WnBa2+ on the number of water molecules are shown to be parabolic, with the energy minima at n = 5 and n = 6, respectively. It is found that Q7 can form in an aqueous solution supramolecular complexes with protonated histamine (HA) and neutral histamine in the presence of Ca2+ ions.

scholarly journals Origin and structure of polar domains in doped molecular crystals

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
E. Meirzadeh ◽  
I. Azuri ◽  
Y. Qi ◽  
D. Ehre ◽  
A. M. Rappe ◽  
...  
Keyword(s):  
Crystal Engineering ◽  
Density Functional ◽  
Molecular Crystals ◽  
Strong Support ◽  
Functional Theory ◽  
Guest Molecules ◽  
Molecular Dynamics Calculations ◽  
Different Temperatures ◽  
Global Understanding

Abstract Doping is a primary tool for the modification of the properties of materials. Occlusion of guest molecules in crystals generally reduces their symmetry by the creation of polar domains, which engender polarization and pyroelectricity in the doped crystals. Here we describe a molecular-level determination of the structure of such polar domains, as created by low dopant concentrations (<0.5%). The approach comprises crystal engineering and pyroelectric measurements, together with dispersion-corrected density functional theory and classical molecular dynamics calculations of the doped crystals, using neutron diffraction data of the host at different temperatures. This approach is illustrated using centrosymmetric α-glycine crystals doped with minute amounts of different L-amino acids. The experimentally determined pyroelectric coefficients are explained by the structure and polarization calculations, thus providing strong support for the local and global understanding of how different dopants influence the properties of molecular crystals.

A DFT-D study of the interaction of methane, carbon monoxide, and nitrogen with cation-exchanged SAPO-34

2015 ◽  
Vol 230 (5) ◽  
Author(s):  
Michael Fischer ◽  
Robert G. Bell
Keyword(s):  
Density Functional Theory ◽  
Carbon Monoxide ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Dispersion Correction ◽  
Functional Theory ◽  
Guest Molecules ◽  
Semi Empirical ◽  
Methane Carbon

AbstractDensity-functional theory calculations including a semi-empirical dispersion correction (DFT-D) are employed to study the interaction of small guest molecules (CH

scholarly journals Complementary Base Lowers the Barrier in SuFEx Click Chemistry for Primary Amine Nucleophiles

2020 ◽  
Author(s):  
Jan-Niclas Luy ◽  
Ralf Tonner
Keyword(s):  
Primary Amine ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Building Blocks ◽  
Energy Decomposition Analysis ◽  
Electronic Effects ◽  
Functional Theory ◽  
Molecular Building Blocks ◽  
Further Development ◽  
Crucial Ingredient

The Sulfur (VI) Fluoride Exchange (SuFEx) reaction is an emerging scheme for connecting molecular building blocks. Due to its broad functional group tolerance and rather stable resulting linkage it is seeing rapid adoption in various fields of chemistry. Still, to date the reaction mechanism is poorly understood which hampers further development. Here, we show that the mechanism of the SuFEx reaction for the prototypical example of methanesulfonyl fluoride reacting with methylamine can be understood as an SN2-type reaction. By analyzing the reaction path with the help of density functional theory in vacuo and under consideration of solvent and co-reactant influence we identify the often used complementary base as crucial ingredient to lower the reaction barrier significantly by increasing the nucleophilicity of the primary amine. With the help of energy decomposition analysis (EDA) at the transition state structures we quantify the underlying stereo-electronic effects and propose new avenues for experimental exploration of the potential of SuFEx chemistry.

Plasmon-induced nonlinear response of silver atomic chains

Nanoscale ◽  
2018 ◽  
Vol 10 (18) ◽  
pp. 8600-8605 ◽  
Author(s):  
Lei Yan ◽  
Mengxue Guan ◽  
Sheng Meng
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Nonlinear Response ◽  
Nonlinear Effects ◽  
Time Dependent ◽  
Microscopic Mechanism ◽  
Functional Theory ◽  
Atomic Chains ◽  
Dependent Density

The microscopic mechanism for plasmon-induced nonlinear effects is revealed using time-dependent density functional theory.

Study on the Enhanced Visible Photocatalysis Activity in Transition Metal Doped ZnS

2013 ◽  
Vol 734-737 ◽  
pp. 2351-2355
Author(s):  
Li Guan ◽  
Ai Ling Wu ◽  
Ting Kun Gu ◽  
Wei Wei Yu
Keyword(s):  
Density Functional ◽  
Microscopic Mechanism ◽  
Electronic Density ◽  
Functional Theory ◽  
Wave Approximation ◽  
Zinc Blende ◽  
Visible Light Range ◽  
Visible Photocatalysis ◽  
Metal Doped ◽  
Plane Wave Approximation

The electronic structure and optical properties of pristine and Pd-doped or Ag-doped zinc blende ZnS were calculated with the ab-initio ultrasoft pseudopotential plane wave approximation method based on density functional theory (DFT). The results show that doping significantly alters the system band structure and the electronic density of states (DOS), effectivly enhancing the ZnS optical response and the photocatalytic activity in the visible light range. The microscopic mechanism shows that ZnS photocatalysis efficiency is observably improved through doping.

Disclosing the microscopic mechanism and adsorption properties of CO2 capture in N-isopropylethylenediamine appended M2(dobpdc) series

2020 ◽  
Vol 22 (42) ◽  
pp. 24614-24623 ◽  
Author(s):  
Hui Zhang ◽  
Li-Ming Yang ◽  
Hui Pan ◽  
Eric Ganz
Keyword(s):  
Density Functional Theory ◽  
Co2 Capture ◽  
Density Functional ◽  
Adsorption Properties ◽  
Microscopic Mechanism ◽  
Functional Theory ◽  
First Time ◽  
Detailed Picture

The detailed picture of the microscopic mechanism for CO2 capture with N-isopropylethylenediamine grafted M2(dobpdc) has been determined for the first time via systematic computations with vdW corrected density functional theory.

A Density Functional Theory Study of Gd8O12 Cluster

2012 ◽  
Vol 542-543 ◽  
pp. 1418-1421
Author(s):  
Qing Xiang Gao ◽  
Lin Xu ◽  
Bo Wu
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Density Functional ◽  
Magnetic Moments ◽  
Generalized Gradient ◽  
Cage Structure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Spin Polarized ◽  
Ionic Bonds

The spin-polarized generalized gradient approximation to the density functional theory is used to determine the geometries, stability, electronic structures, and magnetic properties of the Gd8O12cluster. Our work reveals that the ground state configuration of the Gd8O12cluster is a hexahedral cage structure with Cisymmetry. The electronic and magnetic properties imply that the formations of the ionic bonds between the adjacent Gd and O atoms result in the high stability of the Gd8O12cluster, which is due to the charge transfers between the Gd 5d, 6s electrons to O 2p orbital. It is also confirmed by the electron densities of HOMO-LUMO states. In addition, the analysis of the magnetic properties implies the total magnetic moments are mostly dominated by the Gd 4f orbital.

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