Introducing DDEC6 atomic population analysis: part 3. Comprehensive method to compute bond orders

Manz, Thomas A.

doi:10.1039/c7ra07400j

Cited by 404 publications

(372 citation statements)

References 137 publications

(178 reference statements)

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“…Thus, a practical method to investigate the bond‐response process is to extract the bond length and bond order of broken bonds during the deformation process . Here we applied density derived electrostatic and chemical (DDEC6) atomic population analysis which can track the electronic density overlaps between atoms to compute bond orders . This method applied a modified exchange hole (called the “dressed exchange hole”) instead of the normally pure exchange hole to compute bond orders.…”

Section: Methodsmentioning

confidence: 99%

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Shear‐induced brittle failure of titanium carbide from quantum mechanics simulations

Tang

Shen

2018

J Am Ceram Soc

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Titanium carbide (TiC) has a wide range of engineering applications such as structural components, protective coating materials for cutting tools and strengthening phase because of such superior properties as high wear resistance, high hardness, and good chemical resistance. However, the intrinsic failure mechanism of TiC remains unknown, which limits its extended engineering applications. Here, we used density‐functional theory (DFT) at the Perdew‐Burke‐Ernzerhof (PBE) level to examine the shear‐induced failure mechanism of TiC along various plausible slip systems. We found that the (110)[1 true1false¯ 0] slip system has the lowest critical shear strength under both pure shear and indentation stress conditions, suggesting that it is the most plausible failure system under both conditions. The failure mechanism arises from the Ti–C bond stretching and finally breaking with the increase in shear strain. The deformation modes along other possible slip systems are also investigated, which illustrate the failure mechanism along other slip systems. Our results provide atomistic explanation of the brittle failure of TiC, which will be useful for designing TiC based hard materials with improved mechanical properties.

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Section: Methodsmentioning

confidence: 99%

“…The same spin electrons form the exchange and quantum blurring interactions which lead to bond order. Thus, the delocalization of electrons is described by a mathematical formalism resembling the exchange interactions, as described in the literature …”

Section: Methodsmentioning

confidence: 99%

Shear‐induced brittle failure of titanium carbide from quantum mechanics simulations

Tang

Shen

2018

J Am Ceram Soc

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“…In the chemistry community, it is common practice to use the concept of bond order . Localized orbitals (e.g., NBO) and other concepts can be used to determine bond orders in a post‐processing fashion. In FLO‐SIC, one can define a simple FOD bond order (BO FOD ) as

{BO}_{FOD} = m_{electrons} / n_{centers},

where m is the number of electrons involved in the bond and n is the number of atoms that belong to this bond.…”

Section: Relation Between Fods and Chemical Bonding Informationmentioning

confidence: 99%

Interpretation and Automatic Generation of Fermi‐Orbital Descriptors

et al. 2019

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We present an interpretation of Fermi‐orbital descriptors (FODs) and argue that these descriptors carry chemical bonding information. We show that a bond order derived from these FODs agrees well with reference values, and highlight that optimized FOD positions used within the Fermi‐Löwdin orbital self‐interaction correction (FLO‐SIC) method correspond to expectations from Linnett's double‐quartet theory, which is an extension of Lewis theory. This observation is independent of the underlying exchange‐correlation functional, which is shown using the local spin density approximation, the Perdew–Burke–Ernzerhof generalized gradient approximation (GGA), and the strongly constrained and appropriately normed meta‐GGA. To make FOD positions generally accessible, we propose and discuss four independent methods for the generation of Fermi‐orbital descriptors, their implementation as well as their advantages and drawbacks. In particular, we introduce a re‐implementation of the electron force field, an approach based on the centers of mass of orbital densities, a Monte Carlo‐based algorithm, and a method based on Lewis‐like bonding information. All results are summarized with respect to future developments of FLO‐SIC and related methods. © 2019 The Authors. Journal of Computational Chemistry published by Wiley Periodicals, Inc.

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“…The calculated bond orders are presented together with occupancy bond index (OBI) in Table . The OBI estimates the bond order by subtracting the number of antibonding electrons from bonding electrons and dividing the difference by two . The values from the two different methods agree well up to cluster n= 2.…”

Section: Resultsmentioning

confidence: 96%

Activation of Dinitrogen with a Superalkali Species, Li₃F₂

Park

Meloni

2018

ChemPhysChem

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The capability of the superalkali Li F to activate dinitrogen (N ) is presented. The (Li F )nN clusters (n=1-6) were investigated first at the MP2/6-311+G(3d2f,2df,2p)//B3LYP/6-311G(2d,d,p) level of theory. Clusters up to n=4 were also optimized through the CBS-QB3 composite model. The complete dissociation of N was confirmed through visualized molecular orbitals and bond order calculation. The N-N bond is weakened by the addition of Li F superalkali units. The enthalpy of atomization ΔatH0∘ and formation (ΔfH0∘ ), charge flows (Δq), binding energies, and the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital are calculated to help explain the N activation.

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Introducing DDEC6 atomic population analysis: part 3. Comprehensive method to compute bond orders

Abstract: A new method to compute accurate bond orders for metallic, covalent, polar-covalent, ionic, multi-centered, aromatic, dative, dispersion, and hydrogen bonding.

Cited by 404 publications

References 137 publications

Shear‐induced brittle failure of titanium carbide from quantum mechanics simulations

Shear‐induced brittle failure of titanium carbide from quantum mechanics simulations

Interpretation and Automatic Generation of Fermi‐Orbital Descriptors

Activation of Dinitrogen with a Superalkali Species, Li₃F₂

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Introducing DDEC6 atomic population analysis: part 3. Comprehensive method to compute bond orders

Abstract: A new method to compute accurate bond orders for metallic, covalent, polar-covalent, ionic, multi-centered, aromatic, dative, dispersion, and hydrogen bonding.

Cited by 404 publications

References 137 publications

Shear‐induced brittle failure of titanium carbide from quantum mechanics simulations

Shear‐induced brittle failure of titanium carbide from quantum mechanics simulations

Interpretation and Automatic Generation of Fermi‐Orbital Descriptors

Activation of Dinitrogen with a Superalkali Species, Li3F2

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Activation of Dinitrogen with a Superalkali Species, Li₃F₂