Theoretical studies on clusters of carbonate with carbon dioxide, CO31–/2–(CO2)n, for n = 1–5 — Comparison of carbonate clusters with sulfate clusters

2012 ◽  
Vol 90 (5) ◽  
pp. 483-492 ◽  
Author(s):  
Friedrich Grein ◽  
Daniel M. Chevrier
Keyword(s):  
Carbon Dioxide ◽  
Gas Phase ◽  
Density Functional ◽  
Binding Energies ◽  
Electron Detachment ◽  
Functional Theory ◽  
Solvent Molecules ◽  
Experimental Values ◽  
Carbon Dioxide Clusters ◽  
Small Clusters

Density functional theory (DFT) calculations were performed on the geometries and energies of CO31–/2–(CO2)n clusters with n = 1–5. For small clusters (n = 1 or 2), coupled cluster energies were obtained. Up to three CO2 molecules are bound covalently to the dianion. Only weak electrostatic bonds were found in the monoanions. Calculated binding energies for the monoanions are in reasonable agreement with experimental values. The calculated adiabatic electron detachment energy for the dianion is –0.07 eV at n = 5, indicating that at least six CO2 molecules will have to be added to CO32– before the dianionic cluster becomes, in the gas phase, more stable than the monoanionic one. In comparison, for sulfate – carbon dioxide clusters, stabilization occurs at n = 2. Carbonate clusters are compared with sulfate clusters for three solvent molecules: CO2, SO2, and H2O. Carbonate clusters have larger binding energies than sulfate clusters. For a given dianion, binding energies are largest for SO2 and smallest for H2O. However, in all cases, stabilization of the carbonate dianion by clustering is more difficult to achieve than stabilization of the sulfate dianion.

Nb2BN2− cluster anions reduce four carbon dioxide molecules: reactivity enhancement by ligands

2020 ◽  
Vol 49 (40) ◽  
pp. 14081-14087 ◽  
Author(s):  
Hai-Yan Zhou ◽  
Ming Wang ◽  
Yong-Qi Ding ◽  
Jia-Bi Ma
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Cluster Anions ◽  
Gas Phase Reactions ◽  
Functional Theory ◽  
Flight Mass Spectrometry

The thermal gas-phase reactions of Nb2BN2− cluster anions with carbon dioxide have been explored by using the art of time-of-flight mass spectrometry and density functional theory calculations.

Phthalocyanines core-modified by P and S and their complexes with fullerene C60: DFT study

2019 ◽  
Vol 4 (10) ◽  
Author(s):  
Aleksey E. Kuznetsov
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Structural Features ◽  
Binding Energies ◽  
Functional Theory ◽  
Calculated Binding Energy ◽  
The Core ◽  
The One ◽  
Formation Of Complexes ◽  
Phthalocyanine Ring

Abstract Phthalocyanines (Pcs) and their derivatives have attracted a lot of attention because of their both biological importance and technological applications. The properties of Pcs can be tuned by replacing the central atom, by modifying the periphery of phthalocyanine ring, and by changing the meso-atoms. One more promising pathway for modifying Pcs and their derivatives can be the core-modification, or substitution of the core isoindole nitrogen(s) by other elements. Motivated by the results obtained for some core-modified porphyrins, we investigated computationally complete core-modification of regular Zn phthalocyanine (ZnPc) with P and S. We performed density functional theory studies of the structures, charges, and frontier molecular orbitals of P-core-modified and S-core-modified ZnPcs, ZnPc(P)4 and ZnPc(S)4, using both B3LYP and two dispersion-corrected functionals. Also, we studied computationally formation of complexes between the fullerene C60 and ZnPc(P)4 and ZnPc(S)4. Both ZnPc(P)4 and ZnPc(S)4 show strong bowl-like distortions similar to the results obtained earlier for ZnP(P)4 and ZnP(S)4. The size of the “bowl” cavity of the both core-modified Pcs is essentially the same, showing no dependence on the core-modifying element. For ZnPc(S)4, the HOMO is quite different from those of ZnPc and ZnPc(P)4. When the fullerene C60 forms complexes with the ZnPc(P)4 and ZnPc(S)4 species in the gas phase, it is located relatively far (4.30–5.72 Å) from the one of the P-centers and from the Zn-center of ZnPc(P)4, whereas with ZnPc(S)4 C60 forms relatively short bonds with the Zn-center, varying from ca. 2.0 to ca. 3.0 Å. The very strong deformations of both the ZnPc(P)4 and ZnPc(S)4 structures are observed. The calculated binding energy at the B3LYP/6-31G* level for the C60-ZnPc(P)4 complex is quite low, 1.2 kcal/mol, which agrees with the quite long distances fullerene - ZnPc(P)4, whereas it is noticeably larger, 13.6 kcal/mol, for the C60-ZnPc(S)4 complex which again agrees with the structural features of this complex. The binding energies of the complexes optimized using the dispersion-corrected functionals, CAM-B3LYP and wB97XD, are significantly larger, varying from ca. 14 till 52 kcal/mol which corresponds with the shorter distances between the fullerene and ZnPc(X)4 species.

Density Functional Theory Study of the Interaction of Nitric Oxide with 3D Transition Metal Dimers

2014 ◽  
Vol 804 ◽  
pp. 145-148 ◽  
Author(s):  
Jing Nie ◽  
Rui Jie Li ◽  
Li Jun He ◽  
Jin Li
Keyword(s):  
Nitric Oxide ◽  
Density Functional Theory ◽  
Transition Metal ◽  
Periodic Table ◽  
Density Functional ◽  
Vibrational Frequencies ◽  
Binding Energies ◽  
Functional Theory ◽  
Experimental Values ◽  
The Right

Density-functional theory (DFT) has been used to calculate the interaction of nitric oxide with 3d metal dimers (scandium through zinc) and determine the ground-state geometrical configurations and vibrational frequencies. Results are compared to the relevant experimental values and to other theoretical investigations when available, and the overall agreement has been obtained. On going from left to right side of the Periodic Table, the preference for the coordination mode of NO to transition-metal dimers is from side-on-bonded mode (Sc, Ti, V), via semibridging (Cr), to end-on-bonded mode (Mn, Fe, Co, Ni, Cu). The N-O stretching vibrational frequencies in the ground states of M2NO (M = Sc to Zn) increase generally from the left to the right side of the Periodic Table, whereas the N-O bond lengths decrease generally. The binding energies exhibit an overall decrease trend. These general trends in the interaction of nitric oxide with 3d metal dimers mirror the main features of NO adsorption on transition metal surfaces.

Intrinsic Stacking Interactions of Natural and Artificial Nucleobases

2019 ◽  
Author(s):  
Drew P. Harding ◽  
Laura J. Kingsley ◽  
Glen Spraggon ◽  
Steven Wheeler
Keyword(s):  
Gas Phase ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Molecular Descriptors ◽  
Stacking Interactions ◽  
Interaction Energies ◽  
Functional Theory ◽  
Binding Partner ◽  
Heavy Atoms ◽  
Wide Range

The intrinsic (gas-phase) stacking energies of natural and artificial nucleobases were explored using density functional theory (DFT) and correlated ab initio methods. Ranking the stacking strength of natural nucleobase dimers revealed a preference in binding partner similar to that seen from experiments, namely G > C > A > T > U. Decomposition of these interaction energies using symmetry-adapted perturbation theory (SAPT) showed that these dispersion dominated interactions are modulated by electrostatics. Artificial nucleobases showed a similar stacking preference for natural nucleobases and were also modulated by electrostatic interactions. A robust predictive multivariate model was developed that quantitively predicts the maximum stacking interaction between natural and a wide range of artificial nucleobases using molecular descriptors based on computed electrostatic potentials (ESPs) and the number of heavy atoms. This model should find utility in designing artificial nucleobase analogs that exhibit stacking interactions comparable to those of natural nucleobases. Further analysis of the descriptors in this model unveil the origin of superior stacking abilities of certain nucleobases, including cytosine and guanine.

scholarly journals A Comparative Study of Oxygen and Hydrogen Adsorption on Strained and Alloy-Supported Pt(111) Monolayers

2021 ◽  
Vol 7 (7) ◽  
pp. 101
Author(s):  
Ian Shuttleworth
Keyword(s):  
Comparative Study ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Binding Energies ◽  
High Symmetry ◽  
Density Functionals ◽  
Functional Theory ◽  
Ligand Effects ◽  
Ferromagnetic Alloys ◽  
Depth Study

A comparative study of the unreacted and reacted uniaxially strained Pt(111) and the layered (111)-Pt/Ni/Pt3Ni and (111)-Pt/Ni/PtNi3 surfaces has been performed using density functional theory (DFT). An in-depth study of the unreacted surfaces has been performed to evaluate the importance of geometric, magnetic and ligand effects in determining the reactivity of these different Pt surfaces. An analysis of the binding energies of oxygen and hydrogen over the high-symmetry binding positions of all surfaces has been performed. The study has shown that O and H tend to bind more strongly to the (111)-Pt/Ni/Pt3Ni surface and less strongly to the (111)-Pt/Ni/PtNi3 surface compared to binding on the equivalently strained Pt(111) surfaces. Changes in the surface magnetisation of the surfaces overlaying the ferromagnetic alloys during adsorption are discussed, as well as the behaviour of the d-band centre across all surfaces, to evaluate the potential mechanisms for these differences in binding. An accompanying comparison of the accessible density functionals has been included to estimate the error in the computational binding energies.

A DFT study of spherands containing five anisyl groups — Highly preorganized to bind the alkali metal

2006 ◽  
Vol 84 (8) ◽  
pp. 1045-1049 ◽  
Author(s):  
Shabaan AK Elroby ◽  
Kyu Hwan Lee ◽  
Seung Joo Cho ◽  
Alan Hinchliffe
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Density Functional ◽  
Ionic Radius ◽  
Binding Energies ◽  
Cavity Size ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Good Agreement

Although anisyl units are basically poor ligands for metal ions, the rigid placements of their oxygens during synthesis rather than during complexation are undoubtedly responsible for the enhanced binding and selectivity of the spherand. We used standard B3LYP/6-31G** (5d) density functional theory (DFT) to investigate the complexation between spherands containing five anisyl groups, with CH2–O–CH2 (2) and CH2–S–CH2 (3) units in an 18-membered macrocyclic ring, and the cationic guests (Li+, Na+, and K+). Our geometric structure results for spherands 1, 2, and 3 are in good agreement with the previously reported X-ray diffraction data. The absolute values of the binding energy of all the spherands are inversely proportional to the ionic radius of the guests. The results, taken as a whole, show that replacement of one anisyl group by CH2–O–CH2 (2) and CH2–S–CH2 (3) makes the cavity bigger and less preorganized. In addition, both the binding and specificity decrease for small ions. The spherands 2 and 3 appear beautifully preorganized to bind all guests, so it is not surprising that their binding energies are close to the parent spherand 1. Interestingly, there is a clear linear relation between the radius of the cavity and the binding energy (R2 = 0.999).Key words: spherands, preorganization, density functional theory, binding energy, cavity size.

scholarly journals Defect Properties and Lithium Incorporation in Li2ZrO3

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3963
Author(s):  
Kobiny Antony Rex ◽  
Poobalasuntharam Iyngaran ◽  
Navaratnarajah Kuganathan ◽  
Alexander Chroneos
Keyword(s):  
Atomistic Simulation ◽  
Density Functional ◽  
Functional Theory ◽  
Lithium Zirconate ◽  
Simulation Based ◽  
Electrochemical Devices ◽  
Li Ion ◽  
Cluster Energy ◽  
Experimental Values ◽  
Lithium Incorporation

Lithium zirconate is a candidate material in the design of electrochemical devices and tritium breeding blankets. Here we employ an atomistic simulation based on the classical pair-wise potentials to examine the defect energetics, diffusion of Li-ions, and solution of dopants. The Li-Frenkel is the lowest defect energy process. The Li-Zr anti-site defect cluster energy is slightly higher than the Li-Frenkel. The Li-ion diffuses along the c axis with an activation energy of 0.55 eV agreeing with experimental values. The most favorable isovalent dopants on the Li and Zr sites were Na and Ti respectively. The formation of additional Li in this material can be processed by doping of Ga on the Zr site. Incorporation of Li was studied using density functional theory simulation. Li incorporation is exoergic with respect to isolated gas phase Li. Furthermore, the semiconducting nature of LZO turns metallic upon Li incorporation.

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