scholarly journals Performances of different DFT functionals to calculate the anodic limit of fluorinated sulphonyl-imide anions for lithium cells

2021 ◽  
Vol 2090 (1) ◽  
pp. 012078
Author(s):  
A Paolone ◽  
S Brutti
Keyword(s):  
Ionic Liquids ◽  
Lithium Batteries ◽  
Basis Set ◽  
Basis Sets ◽  
Computational Time ◽  
Generalized Gradient ◽  
Neutral Species ◽  
Generalized Gradient Approximation ◽  
Model Based ◽  
Computationally Expensive

Abstract In this paper we investigated the calculation of the anodic limit of two anions of ionic liquids, largely used as electrolyte of lithium batteries. Starting from a model based on calculations performed on single ions at the MP2 level of theory, we showed that the matching between calculation and experiments decreases while using more expanded basis set with respect to 6-31G**, possibly because of the destabilization of the neutral species when larger basis sets are considered. Additionally, in order to decrease the computational time, the performances for the calculation of the anodic limit obtained by means of a series of DFT functionals with increasing level of complexity (from the Generalized Gradient Approximation to the Range Separated Hybrid meta-Generalized Gradient Approximation) were compared. Overall, the best performing functionals are BMK, ωB97M-V and MN12-SX, while acceptable results can be obtained by M06-2X, M11, M08-HX and M11-L. Some less computationally expensive functionals, like CAM-B3LYP and ωB97X-D, also provide reasonable values of the anodic limit.

Dissociation of dinitrogen on iron clusters: A detailed study of the Fe16 + N2 case.

2020 ◽  
Author(s):  
Bole Chen ◽  
Gennady L. Gutsev ◽  
Weiguo Sun ◽  
Xiao-Yu Kuang ◽  
Cheng Lu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Basis Set ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Iron Clusters ◽  
Generalized Gradient Approximation

The coalescence of two Fe8N as well as the structure of the Fe16N2 cluster were studied using density functional theory with the generalized gradient approximation and a basis set of...

scholarly journals Quasi-Relativistic Calculation of EPR g-Tensors with Derivatives of the Decoupling Transformation, Gauge-Including Atomic Orbitals, and Magnetic Balance

2021 ◽  
Author(s):  
Yannick J. Franzke ◽  
Jason M. Yu
Keyword(s):  
Density Functional ◽  
Hyperfine Coupling Constant ◽  
Basis Set ◽  
Basis Sets ◽  
Generalized Gradient ◽  
Atomic Orbitals ◽  
Experimental Findings ◽  
The Impact ◽  
Derivatives Of ◽  
Magnetic Balance

We present an exact two-component (X2C) ansatz for the EPR g-tensor using gauge-including atomic orbitals (GIAOs) and a magnetically balanced basis set expansion. In contrast to previous X2C and "fully" relativistic ansätze for the g-tensor, this implementation results in a gauge-origin invariant formalism. Furthermore, the derivatives of the relativistic decoupling matrix are considered to form the complete analytical derivative of the X2C Hamiltonian. To reduce the associated computational costs, we apply the diagonal local approximation to the unitary decoupling transformation (DLU) and the (multipole-accelerated) resolution of the identity approximation. The X2C ansatz is compared to Douglas-Kroll-Hess theory and the zeroth-order regular approximation for 11 diatomic molecules. The impact of the relativistic Hamiltonian, the basis set, and the density functional approximation is subsequently assessed for a set of 17 transition-metal complexes to complement our previous work on the hyperfine coupling constant [DOI: 10.33774/chemrxiv-2021-wnz1v-v2]. In total, 24 basis sets and 22 density functional approximations are considered. The quasi-relativistic X2C and DLU-X2C Hamiltonians accurately reproduce the results of the parent "fully" relativistic four-component theory when accounting for two-electron picture-change effects with the modified screened nuclear spin-orbit approximation in the respective one-electron integrals and integral derivatives. Generally, the uncontracted Dyall and segmented-contracted Karlsruhe x2c-type basis sets perform well when compared to large even-tempered basis sets. Moreover, (range-separated) hybrid density functional approximations are needed to match the experimental findings. Here, hybrids based on the meta -generalized gradient approximation are not an a priori improvement. Compared to the other computational parameters, the impact of the GIAOs and the magnetic balance on the actual results in standard calculations is less pronounced. Routine calculations of large molecules are possible with widely available and comparably low- cost hardware as demonstrated for [Pt(C6Cl5)4]− with 3360 basis functions and three spin-(1/2) La(II) and Lu(II) compounds. Both approaches based on a common gauge origin and GIAOs using triple- ζ basis sets lead to a good agreement with the experimental findings. The best agreement is found with hybrid functionals such as PBE0 and ωB97X-D.

scholarly journals Norm-Conserving Pseudopotentials and Basis Sets to Explore Actinide Chemistry in Complex Environments

2021 ◽  
Author(s):  
Jun-Bo Lu ◽  
David Cantu ◽  
Cong-Qiao Xu ◽  
Manh-Thuong Nguyen ◽  
Han-Shi Hu ◽  
...  
Keyword(s):  
Oxidation States ◽  
Basis Sets ◽  
Complex Environments ◽  
Large Core ◽  
Generalized Gradient ◽  
Gaussian Basis Sets ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Core Set ◽  
Critical Void

We have developed a new set of norm-conserving pseudopotentials and companion Gaussian basis sets for the actinide (An) series (Ac - Lr) using the Goedecker, Teter and Hutter (GTH) formalism with the Perdew, Burke and Ernzerhof (PBE) exchange-correlation functional of generalized gradient approximation (GGA). To test the accuracy and reliability of the newly parameterized An-GTH pseudopotentials and basis sets, a variety of benchmarks on actinide-containing molecules are carried out and compared to all-electron and available experimental results. The new pseudopotentials include both medium- ([Xe]4f14) and large-core ([Xe]4f145d10) options that have successfully reproduced structures and energetics, particularly redox processes. The medium-core size set, in particular, reproduce all-electron calculations over multiple oxidation states from 0 to VII, whereas the large-core set is suitable only for the early series elements and low oxidation states. The underlying reason for these transferability issues are discussed in detail. This work fills a critical void in the literature for studying the chemistry of 5f-block elements in condensed phase.

Effect of Basis Sets on the Selection of the Level of Theory Toward the Development of Quantum-Based Force Field Equation for Ionic Liquids

2005 ◽  
Vol 5 (2) ◽  
pp. 156 ◽  
Author(s):  
A. N. Soriano ◽  
B. T. Doma, Jr.
Keyword(s):  
Ionic Liquids ◽  
Field Equation ◽  
Volatile Organic Compounds ◽  
Force Field ◽  
Organic Compounds ◽  
Basis Set ◽  
Basis Sets ◽  
Hartree Fock ◽  
Volatile Organic ◽  
Selection Of

The chemical industry is under considerable pressure to replace many of the volatile organic compounds. Volatile organic compounds are a major contributor to air pollution, but out of necessity, they are still frequently used in many chemical and industrial processes. A new class of solvents, referred to as ionic liquids, may offer at least a partial solution to the pollution problem caused by volatile organic compounds. Ionic liquids are generally considered "green" solvents because of their environment-friendly properties. However, the main problem that hinders the chemical industry from using ionic liquids is that, compared to conventional organic solvents, relatively little is known about their thermodynamic and transport properties. Since there are large possible combinations of ionic liquids, it would be very expensive if the study were conducted in the laboratory. The more appropriate approach in studying the properties of ionic liquids is to engage in a computational method, which uses a computer software that evaluates ionic liquids' thermophysical quantities via quantum mechanical and molecular mechanical simulations. In this study, a computer simulation, with the aid of SPARTAN '02 software, is used to study the effect of basis sets on the selection of the appropriate level of theory, which would be employed later in developing a quantum-based force field equation for predicting the properties of ionic liquids. Using the Hartree-Fock self-consistent filled (HF-SCF) molecular orbital model with different basis sets, a single point energy calculations were carried out for the chosen ionic liquid. With the exception of the minimal basis set, the SCF total energies for the other basis sets agree with each other in terms of magnitude. The SCF total energy is not affected as the basis set varies from minimal to split valence and as it polarizes. The most appropriate basis set was found to be 6-31G*. Keywords: Basis sets, Hartree-Fock, ionic liquids, force field equation, level of theory, and SPARTAN '02.

Magnetic Properties of Mn Doped NiO

2008 ◽  
Vol 55-57 ◽  
pp. 857-860 ◽  
Author(s):  
Ekaphan Swatsitang ◽  
A. Pimsawat
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Plane Wave ◽  
Density Functional ◽  
Program Package ◽  
Basis Set ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Mn Doped

ABINIT program package based on Density Functional Theory (DFT) within the Generalized Gradient Approximation (GGA) and plane wave basis set are used to calculate the magnetic properties of Mn doped NiO. It was found that the magnetic properties of Mn doped NiO were changed from anti-ferromagnetic (pure NiO) to ferromagnetism. Increasing the concentrations of Mn, the magnetization of Mn doped NiO were increased (Ni31MnO32 = 66.69 µB, Ni30Mn2O32 = 69.59 µB and Ni29Mn3O32 = 72.42 µB).

Norm-Conserving Pseudopotentials and Basis Sets Optimized for Lanthanide Molecules and Solid-State Compounds

2019 ◽  
Author(s):  
Junbo Lu ◽  
David Cantu ◽  
Manh-Thuong Nguyen ◽  
Jun Li ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Solid State ◽  
Basis Sets ◽  
Generalized Gradient ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Gaussian Type ◽  
Lanthanide Elements ◽  
Complete Set ◽  
Pseudo Potential

A complete set of pseudopotentials and corresponding basis sets for all lanthanide elements are presented based on the relativistic, norm-conserving, Gaussian-type pseudo potential protocol of Goedecker, Teter, and Hutter (GTH) within the generalized gradient approximation and exchange-correlation functional of Perdew, Burke, and Ernzerhof. The accuracy and reliability of our GTH pseudopotentials and companion basis sets optimized for lanthanides is illustrated by a series of test calculations on lanthanide-containing molecules and solid-state systems.

Norm-Conserving Pseudopotentials and Basis Sets Optimized for Lanthanide Molecules and Solid-State Compounds

2019 ◽  
Author(s):  
Junbo Lu ◽  
David Cantu ◽  
Manh-Thuong Nguyen ◽  
Jun Li ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Solid State ◽  
Basis Sets ◽  
Generalized Gradient ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Gaussian Type ◽  
Lanthanide Elements ◽  
Complete Set ◽  
Pseudo Potential

A complete set of pseudopotentials and corresponding basis sets for all lanthanide elements are presented based on the relativistic, norm-conserving, Gaussian-type pseudo potential protocol of Goedecker, Teter, and Hutter (GTH) within the generalized gradient approximation and exchange-correlation functional of Perdew, Burke, and Ernzerhof. The accuracy and reliability of our GTH pseudopotentials and companion basis sets optimized for lanthanides is illustrated by a series of test calculations on lanthanide-containing molecules and solid-state systems.

Establishing the accuracy of density functional approaches for the description of noncovalent interactions in ionic liquids

2021 ◽  
Author(s):  
Minho Kim ◽  
Tim Gould ◽  
Ekaterina I. Izgorodina ◽  
Dario Rocca ◽  
Sebastien Lébegue
Keyword(s):  
Ionic Liquids ◽  
Density Functional ◽  
Noncovalent Interactions ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation

We test a number of dispersion corrected versatile Generalized Gradient Approximation (GGA) and meta-GGA functionals for their ability to predict the interactions of ionic liquids, and show that most can...

scholarly journals Norm-Conserving Pseudopotentials and Basis Sets to Explore Actinide Chemistry in Complex Environments

2021 ◽  
Author(s):  
Jun-Bo Lu ◽  
David Cantu ◽  
Cong-Qiao Xu ◽  
Manh-Thuong Nguyen ◽  
Han-Shi Hu ◽  
...  
Keyword(s):  
Oxidation States ◽  
Basis Sets ◽  
Complex Environments ◽  
Large Core ◽  
Generalized Gradient ◽  
Gaussian Basis Sets ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Core Set ◽  
Critical Void

We have developed a new set of norm-conserving pseudopotentials and companion Gaussian basis sets for the actinide (An) series (Ac - Lr) using the Goedecker, Teter and Hutter (GTH) formalism with the Perdew, Burke and Ernzerhof (PBE) exchange-correlation functional of generalized gradient approximation (GGA). To test the accuracy and reliability of the newly parameterized An-GTH pseudopotentials and basis sets, a variety of benchmarks on actinide-containing molecules are carried out and compared to all-electron and available experimental results. The new pseudopotentials include both medium- ([Xe]4f14) and large-core ([Xe]4f145d10) options that have successfully reproduced structures and energetics, particularly redox processes. The medium-core size set, in particular, reproduce all-electron calculations over multiple oxidation states from 0 to VII, whereas the large-core set is suitable only for the early series elements and low oxidation states. The underlying reason for these transferability issues are discussed in detail. This work fills a critical void in the literature for studying the chemistry of 5f-block elements in condensed phase.

scholarly journals Norm-Conserving Pseudopotentials and Basis Sets Optimized for Lanthanide Molecules and Solid-State Compounds

2019 ◽  
Author(s):  
Junbo Lu ◽  
David Cantu ◽  
Manh-Thuong Nguyen ◽  
Jun Li ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Solid State ◽  
Basis Sets ◽  
Generalized Gradient ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Gaussian Type ◽  
Lanthanide Elements ◽  
Complete Set ◽  
Pseudo Potential

A complete set of pseudopotentials and corresponding basis sets for all lanthanide elements are presented based on the relativistic, norm-conserving, Gaussian-type pseudo potential protocol of Goedecker, Teter, and Hutter (GTH) within the generalized gradient approximation and exchange-correlation functional of Perdew, Burke, and Ernzerhof. The accuracy and reliability of our GTH pseudopotentials and companion basis sets optimized for lanthanides is illustrated by a series of test calculations on lanthanide-containing molecules and solid-state systems.

Sign in / Sign up

Export Citation Format

Share Document