MICROHYDRATION OF HYDRONIUM ION AND ZÜNDEL ION: A MANY-BODY ANALYSIS APPROACH

2010 ◽  
Vol 09 (supp01) ◽  
pp. 177-187 ◽  
Author(s):  
AJAY CHAUDHARI ◽  
SHYI-LONG LEE
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Density Functional Method ◽  
Solvation Shell ◽  
Functional Method ◽  
Binding Energies ◽  
Analysis Approach ◽  
Many Body ◽  
Relaxation Energy ◽  
Hydronium Ion

Studying the solvation of an extra proton is important for understanding the proton transfer mechanism in polymer electrolyte membrane fuel cell. We study the interaction of hydronium ion and Zündel ion with water molecules in their first solvation shell using density functional method. A many-body analysis approach has been used to know the contribution of many-body energies to the binding energy of the hydronium ion–(water)3 and Zündel ion–(water)4 hydrogen bonded complex. It was observed that not only two-body energies but three-body and four-body energies also contribute significantly to the binding energy of the hydronium ion–(water)3 and Zündel ion–(water)4 complexes. The binding energy for the former is -32.14 kcal/mol whereas that for the latter is -48.48 kcal/mol. The percentage contributions of the many-body energies to the binding energies for these complexes are reported. The contribution from the relaxation energy to the binding energy of hydronium ion–(water)3 and Zündel ion–(water)4 complexes is 6% and 4.58%, respectively.

Density Functional Theory Study of Intermolecular Interaction between RDX and H2O

2013 ◽  
Vol 750-752 ◽  
pp. 1848-1851
Author(s):  
Xiu Lin Zeng ◽  
Xue Hai Ju
Keyword(s):  
Density Functional ◽  
Natural Bond Orbital ◽  
Density Functional Method ◽  
Zero Point ◽  
Functional Method ◽  
Binding Energies ◽  
Basis Set ◽  
Free Energies ◽  
Functional Theory ◽  
Dimerization Process

The density functional method of wB97xD in combination of 6-31+G** basis set was applied to the study of the heterodimers between hexahydro-1,3,5-trinitro-1,3,5-triazine and water. Three stable dimers were located. The binding energies have been corrected for the zero-point vibrational and basis set superposition errors. The largest corrected binding energy is 26.21 kJ/mol. Natural bond orbital analyses and frequency calculations were performed on each optimized structure. The thermodynamic properties of enthalpies, entropies and Gibbs free energies in the dimerization process were presented.

scholarly journals Computer Simulation of Small Magnetic Clusters of 3d-Transition Metals of the Iron Subgroup Using the Hybrid Density Functional Method

2020 ◽  
pp. 21-26
Author(s):  
S.A. Beznosyuk ◽  
A.G. Blyum ◽  
M.S. Zhukovsky ◽  
T.M. Zhukovsky ◽  
А.S. Masalimov
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
Density Functional Method ◽  
Calculated Data ◽  
Functional Method ◽  
Binding Energies ◽  
Basis Set ◽  
Magnetic Clusters ◽  
Spin Multiplicity ◽  
Hybrid Density Functional

This paper presents the results of s study focused on the stability of small 3d-transition-metal magnetic clusters (metals of an iron subgroup) in spin-polarized states using the hybrid density functional method. Computer modeling and full variational optimization of geometric structures of clusters were performed for various values of the spin multiplicity of electronic states. The binding energies, the bond lengths, and the frequencies of atomic zero-point vibrations in small clusters with a nuclearity of n = 2, 3, 4, 5, 6 were calculated depending on the metal (Fe, Co, Ni) and spin multiplicity M in the zero-charge state. The calculations were carried out using the hybrid density functional B3LYP method in the def2-TZVP basis set of the ORCA package algorithms. A comparison of the calculated results with the available experimental data is presented. It is shown that the calculated data obtained by the hybrid density functional method are in satisfactory agreement with the experimental data for “naked” clusters in inert media both for the spin multiplicity of the ground state and for the energy of atomic shock dissociation of clusters in inert gas flows.

scholarly journals Self-interaction error overbinds water clusters but cancels in structural energy differences

2020 ◽  
Vol 117 (21) ◽  
pp. 11283-11288 ◽  
Author(s):  
Kamal Sharkas ◽  
Kamal Wagle ◽  
Biswajit Santra ◽  
Sharmin Akter ◽  
Rajendra R. Zope ◽  
...  
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Water Clusters ◽  
Local Density ◽  
Correction Method ◽  
Binding Energies ◽  
Total Binding Energy ◽  
Many Body ◽  
Generalized Gradient ◽  
Body Components

We gauge the importance of self-interaction errors in density functional approximations (DFAs) for the case of water clusters. To this end, we used the Fermi–Löwdin orbital self-interaction correction method (FLOSIC) to calculate the binding energy of clusters of up to eight water molecules. Three representative DFAs of the local, generalized gradient, and metageneralized gradient families [i.e., local density approximation (LDA), Perdew–Burke–Ernzerhof (PBE), and strongly constrained and appropriately normed (SCAN)] were used. We find that the overbinding of the water clusters in these approximations is not a density-driven error. We show that, while removing self-interaction error does not alter the energetic ordering of the different water isomers with respect to the uncorrected DFAs, the resulting binding energies are corrected toward accurate reference values from higher-level calculations. In particular, self-interaction–corrected SCAN not only retains the correct energetic ordering for water hexamers but also reduces the mean error in the hexamer binding energies to less than 14 meV/H2Ofrom about 42 meV/H2Ofor SCAN. By decomposing the total binding energy into many-body components, we find that large errors in the two-body interaction in SCAN are significantly reduced by self-interaction corrections. Higher-order many-body errors are small in both SCAN and self-interaction–corrected SCAN. These results indicate that orbital-by-orbital removal of self-interaction combined with a proper DFA can lead to improved descriptions of water complexes.

Theoretical Study on the Electronic Structures, Magnetic Properties and Corrosion-Resistant Ability of NinAl (n=1-8, 12) Clusters

2016 ◽  
Vol 852 ◽  
pp. 55-64
Author(s):  
Shou Gang Chen ◽  
Mei Yan Yu
Keyword(s):  
Magnetic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Density Functional Method ◽  
Aluminum Atom ◽  
Nickel Atom ◽  
Functional Method ◽  
Binding Energies ◽  
Bimetallic Clusters ◽  
Fragmentation Energy

The growth behavior, electronic structures and magnetic properties for NinAl (1-8,12) clusters were investigated detailedly using the selected density functional method (BPW91/LanL2DZ). The change of binding energies show that bimetallic clusters are more stable based on the computed bond energy of Al-Ni, which is bigger than that of Ni-Ni. The strong peaks of Ni5Al in run chart of binding energies, HOMO–LUMO gap, fragmentation energy, the second-order energy and the ionization potential indicate that the stability of bimetallic cluster is optimal when the doping of aluminum is 16.7 atomic percent. At the same time, the hardness analysis of bimetallic clusters shows that Ni5Al cluster has excellent corrosion resistance ability. In addition, the magnetic moment of NinAl (n=1-8,12) clusters decrease obviously comparing with pure nickel clusters because of the s-p-d hybridization between aluminum atom and nickel atom.

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.

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