Electronic and Hydrogen Storage Properties of Li-Terminated Linear Boron Chains Studied by TAO-DFT

Seenithurai, S.; Chai, Jeng-Da

doi:10.1038/s41598-018-31947-9

Cited by 34 publications

(36 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(3) , we calculate the symmetrized von Neumann entropy 16,50,51,54,[56][57][58][59][60][61][62]69 using spin-unrestricted TAO-LDA. Here, the occupation number f i,σ of the i th σ-spin orbital (i.e., up-spin orbital or down-spin orbital) obtained with spin-unrestricted TAO-LDA, which ranges from 0 to 1, is closely related to the occupation number of the i th σ-spin natural orbital 49-51 .…”

Section: Vertical Ionization Potential Vertical Electron Affinity Amentioning

confidence: 99%

“…Besides, aiming to improve the accuracy of TAO-DFT for a wide range of applications, a self-consistent scheme determining the fictitious temperature θ in TAO-DFT has been recently proposed 53 . Since TAO-DFT is a computationally efficient electronic structure method, a number of strongly correlated electron systems at the nanoscale have been studied using TAO-DFT in recent years 16,[54][55][56][57][58][59][60][61][62] . Besides, TAO-DFT has been recently shown to be useful in describing the vibrational spectra of molecules with radical nature 63 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

TAO-DFT investigation of electronic properties of linear and cyclic carbon chains

Seenithurai

Chai

2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

it has been challenging to adequately investigate the properties of nanosystems with radical nature using conventional electronic structure methods. We address this challenge by calculating the electronic properties of linear carbon chains (l-cc[n]) and cyclic carbon chains (c-cc[n]) with n = 10-100 carbon atoms, using thermally-assisted-occupation density functional theory (TAO-DFT). For all the cases investigated, l-cc[n]/c-cc[n] are ground-state singlets, and c-cc[n] are energetically more stable than l-cc[n]. the electronic properties of l-cc[n]/c-cc[n] reveal certain oscillation patterns for smaller n, followed by monotonic changes for larger n. For the smaller carbon chains, odd-numbered l-cc[n] are more stable than the adjacent even-numbered ones; c-cc[4m + 2]/c-CC[4m] are more/less stable than the adjacent odd-numbered ones, where m are positive integers. As n increases, l-cc[n]/c-cc[n] possess increasing polyradical nature in their ground states, where the active orbitals are delocalized over the entire length of l-cc[n] or the whole circumference of c-cc[n]. Carbon is the most versatile element in forming various structures. In bulk phase, graphite and diamond, which are well-known materials, have been used for centuries. In nanoforms, fullerenes and graphene have been studied in detail for decades. In general, nanostructures can be classified into three categories: zero-dimensional (0D), one-dimensional (1D), and two-dimensional (2D) nanomaterials. Carbon forms all these nanostructures with unique shapes and properties. Over the past few decades, carbon nanomaterials have been widely studied, and applied in diverse industries 1-3. A number of carbon nanostructures have been synthesized and applied in different fields. The 0D carbon nanomaterials include clusters, quantum dots, nanoflakes, and buckyballs 3. Among them, the C 60 fullerene molecule (containing 12 pentagons and 20 hexagons), where the carbon atoms are sp 2-sp 3-hybridized, has been a popular carbon nanomaterial 1. The discovery of C 60 has led to the flourishment of carbon nanomaterials in various ways. Graphite is a bulk layered material, where the sp 2-hybridized carbon atoms in each layer are arranged in a hexagonal lattice. The 2D carbon nanomaterial, graphene, can be obtained by mechanically exfoliating a single layer of carbon atoms from graphite 2. Thus, graphene, which is a perfect arrangement of hexagons made up of sp 2-hybridized carbon atoms in a 2D planar surface, can be the thinnest (i.e., single-atom-thick) material synthesized ever. Graphene is a zero-gap semiconductor or semimetal with massless Dirac fermions with linear dispersion at low energy. Because of the Dirac-cone feature, graphene has huge potential in electronics applications 2. The discovery of graphene has also led to the discovery of other 2D materials. Besides, if a graphene sheet can be rolled up to form a seamless cylinder, one obtains a carbon nanotube (CNT), which belongs to the class of 1D nanostructures. Note that CNTs were first observed by Iijima in 19...

show abstract

Section: Vertical Ionization Potential Vertical Electron Affinity Amentioning

confidence: 99%

mentioning

confidence: 99%

TAO-DFT investigation of electronic properties of linear and cyclic carbon chains

Seenithurai

Chai

2020

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…In a finite-temperature approach, the fractional orbital occupation numbers are determined by the orbital energies according to some smearing scheme that is typically controlled by a single parameter, an electronic temperature. Because of the simplicity and favorable computational scaling of FT-DFT, it has become a powerful tool for approximate modeling of systems exhibiting strong correlation; such approaches have been used to obtain promising re-sults for a variety of systems [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Fully numerical calculations on atoms with fractional occupations and range-separated exchange functionals

Lehtola

2020

Phys. Rev. A

View full text Add to dashboard Cite

A recently developed finite element approach for fully numerical atomic structure calculations [S. Lehtola, Int. J. Quantum Chem. 119, e25945 (2019)] is extended to the description of atoms with spherically symmetric densities via fractionally occupied orbitals. Specialized versions of Hartree-Fock as well as local density and generalized gradient approximation density functionals are developed, allowing extremely rapid calculations at the basis set limit on the ground and low-lying excited states even for heavy atoms.The implementation of range-separation based on the Yukawa or complementary error function (erfc) kernels is also described, allowing complete basis set benchmarks of modern range-separated hybrid functionals with either integer or fractional occupation numbers. Finally, computation of atomic effective potentials at the local density or generalized gradient approximation levels for the superposition of atomic potentials (SAP) approach [S. Lehtola, J. Chem. Theory Comput. 15, 1593] that has been shown to be a simple and efficient way to initialize electronic structure calculations is described.The present numerical approach is shown to afford beyond microhartree accuracy with a small number of numerical basis functions, and to reproduce literature results for the ground states of atoms and their cations for 1 ≤ Z ≤ 86. Our results indicate that the literature values deviate by up to 10 µE h from the complete basis set limit. The numerical scheme for the erfc kernel is shown to work by comparison to results from large Gaussian basis set calculations from the literature. Spin-restricted ground states are reported for Hartree-Fock and Hartree-Fock-Slater calculations with fractional occupations for 1 ≤ Z ≤ 118.

show abstract

“…Finite-Temperature DFT, also called thermally assisted-occupation DFT [22], is a useful tool for systems with a complicated electronic structure [23,24]. Besides its utility to select active orbitals prone to partial occupation, as the first step for more sophisticated multiconfigurational or complete active space self-consistent field (MCSCF/CASSCF) treatments, it has been recently applied to a large set of radical and radicaloid systems [25][26][27][28][29]. It is also conceived as a low-cost tool to explore energy landscapes with varying biradical character, as it may happen in organic chemical reactions, and to discard pathological cases in datasets more effectively than using traditional descriptors [30].…”

Section: Summary Of Some Emerging Dft Methodsmentioning

confidence: 99%

Emerging DFT Methods and Their Importance for Challenging Molecular Systems with Orbital Degeneracy

Maroto

Sancho‐García

2019

Computation

View full text Add to dashboard Cite

We briefly present some of the most modern and outstanding non-conventional density-functional theory (DFT) methods, which have largely broadened the field of applications with respect to more traditional calculations. The results of these ongoing efforts reveal that a DFT-inspired solution always exists even for pathological cases. Among the set of emerging methods, we specifically mention FT-DFT, OO-DFT, RSX-DFT, MC-PDFT, and FLOSIC-DFT, complementing the last generation of existing density functionals, such as local hybrid and double-hybrid expressions.

show abstract

Electronic and Hydrogen Storage Properties of Li-Terminated Linear Boron Chains Studied by TAO-DFT

Cited by 34 publications

References 66 publications

TAO-DFT investigation of electronic properties of linear and cyclic carbon chains

TAO-DFT investigation of electronic properties of linear and cyclic carbon chains

Fully numerical calculations on atoms with fractional occupations and range-separated exchange functionals

Emerging DFT Methods and Their Importance for Challenging Molecular Systems with Orbital Degeneracy

Contact Info

Product

Resources

About