Electronic Properties of Cyclacenes from TAO-DFT

Wu, Chun-Shian; Lee, Pei-Yin; Chai, Jeng-Da

doi:10.1038/srep37249

Cited by 56 publications

(122 citation statements)

References 60 publications

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“…Besides, existing XC density functionals in KS-DFT may also be adopted in TAO-DFT. Due to its computational efficiency and reasonable accuracy for large systems with strong static correlation, TAO-DFT has been successfully applied to the study of several strongly correlated electron systems at the nanoscale [14,[49][50][51], which are typically regarded as "challenging systems" for traditional electronic structure methods (e.g., KS-DFT with conventional XC density functionals and single-reference ab initio methods) [44]. Accordingly, TAO-DFT can be an ideal theoretical method for studying the electronic properties of Li 2 C n .…”

Section: Introductionmentioning

confidence: 99%

Effect of Li Termination on the Electronic and Hydrogen Storage Properties of Linear Carbon Chains: A TAO-DFT Study

Seenithurai

Chai

2017

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Accurate prediction of the electronic and hydrogen storage properties of linear carbon chains (Cn) and Li-terminated linear carbon chains (Li2Cn), with n carbon atoms (n = 5–10), has been very challenging for traditional electronic structure methods, due to the presence of strong static correlation effects. To meet the challenge, we study these properties using our newly developed thermally-assisted-occupation density functional theory (TAO-DFT), a very efficient electronic structure method for the study of large systems with strong static correlation effects. Owing to the alteration of the reactivity of Cn and Li2Cn with n, odd-even oscillations in their electronic properties are found. In contrast to Cn, the binding energies of H2 molecules on Li2Cn are in (or close to) the ideal binding energy range (about 20 to 40 kJ/mol per H2). In addition, the H2 gravimetric storage capacities of Li2Cn are in the range of 10.7 to 17.9 wt%, satisfying the United States Department of Energy (USDOE) ultimate target of 7.5 wt%. On the basis of our results, Li2Cn can be high-capacity hydrogen storage materials that can uptake and release hydrogen at temperatures well above the easily achieved temperature of liquid nitrogen.

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Section: Introductionmentioning

confidence: 99%

Effect of Li Termination on the Electronic and Hydrogen Storage Properties of Linear Carbon Chains: A TAO-DFT Study

Seenithurai

Chai

2017

Sci Rep

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“…Recently, linear n-acenes (C 4n+2 H 2n+4 ), containing n linearly fused benzene rings (see Figure 10), have attracted considerable interest in the research community owing to their promising electronic properties [20,21,[45][46][47][48][109][110][111][112][113][114][115][116][117][118][119][120][121][122][123][124]. The electronic properties of nacenes have been found to be highly dependent on the chain lengths.…”

Section: Electronic Properties Of Linear Acenesmentioning

confidence: 99%

“…To reduce the SCE problems with low computational complexity, we have recently developed thermally-assisted-occupation density functional theory (TAO-DFT) [20,21], an efficient electronic structure method for studying the ground-state properties of very large systems (e.g., containing up to a few thousand electrons) with strong static correlation effects [45][46][47][48]. Unlike finite-temperature DFT [49], TAO-DFT is developed for ground-state systems at zero temperature.…”

Section: Introductionmentioning

confidence: 99%

Role of exact exchange in thermally-assisted-occupation density functional theory: A proposal of new hybrid schemes

Chai

2017

The Journal of Chemical Physics

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138

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We propose hybrid schemes incorporating exact exchange into thermally-assisted-occupation density functional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] for an improved description of nonlocal exchange effects. With a few simple modifications, global and range-separated hybrid functionals in Kohn-Sham density functional theory (KS-DFT) can be combined seamlessly with TAO-DFT. In comparison with global hybrid functionals in KS-DFT, the resulting global hybrid functionals in TAO-DFT yield promising performance for systems with strong static correlation effects (e.g., the dissociation of H 2 and N 2 , twisted ethylene, and electronic properties of linear acenes), while maintaining similar performance for systems without strong static correlation effects. Besides, a reasonably accurate description of noncovalent interactions can be efficiently achieved through the inclusion of dispersion corrections in hybrid TAO-DFT. Relative to semilocal density functionals in TAO-DFT, global hybrid functionals in TAO-DFT are generally superior in performance for a wide range of applications, such as thermochemistry, kinetics, reaction energies, and optimized geometries.

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“…Besides experimental work on [ n ]cyclacenes, several computational studies using semi‐empirical methods and ab initio methods have been carried out on these systems. The semi‐empirical work was focused both on an analysis of the structural properties of the cyclacenes as well as the behavior of electronic properties such as the HOMO–LUMO gap as a function of the system size parameter n .…”

Section: Introductionmentioning

confidence: 99%

“…First principles ab initio studies mainly concentrated on the ground‐state character of the wave function and the corresponding excitation energy to the first electronically excited state. Recent studies have shown that the ground state is a singlet state of open‐shell character, with an increasing number of unpaired electrons with increasing system size. This fact in particular, is believed as one of the causes of the difficulties in the synthesis of cyclacenes as it was already argued in the reviews aforementioned.…”

Section: Introductionmentioning

confidence: 99%

A theoretical study on cyclacenes: Analytical tight‐binding approach

Battaglia

Bendazzoli

et al. 2018

Int J of Quantum Chemistry

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We present a theoretical study of cyclacene molecules performed at tight-binding level. The orbital energies and eigenvectors have been analytically computed, and exact expressions for the axial component of the total position spread and polarizability tensors have been obtained. In absence of dimerization, the system has a D nh symmetry, where n is the number of hexagonal units. The energy bands present no gap at the Fermi level, and to this fact it corresponds a diverging (perelectron) polarizability for n ! 1 in the direction of the system symmetry axis. The two (degenerate) components of the polarizability on the r h symmetry plane, conversely, remain finite for n ! 1. The total position spread tensor presents a qualitatively different behavior, since all the three components of the position spread per electron remain finite for n ! 1. The results are analyzed and discussed for both axial and planar components separately as these are affected differently with respect to the increasing system size. Both dipole polarizability and total position spread have been computed using an ab initio approach for the smallest systems, to compare the analytical tight-binding expressions with a higher-level theory. K E Y W O R D Scomplete active space self-consistent field, cyclacenes, polarizability, tight-binding, total position spread 1 | I N TR ODU C TI ON First imagined by Edgar Heilbronner in 1954, [1] [n]cyclacenes (cyclic polyacenes) have been a fascinating research topic. A thorough understanding of cyclacenes is important as they could be considered as the shortest zigzag carbon nanotube (CNT) and could be used to model finite-length CNTs in simulations. Furthermore, [n]cyclacene chains have the potential to be used as precursors for the synthesis of zigzag CNTs, allowing for a more controlled way to fabricate this type of carbon nanostructure. [2] Unfortunately, the synthesis of [n]cyclacenes has not yet been realized as it is summarized in a number of reviews. [3][4][5] Besides experimental work on [n]cyclacenes, several computational studies using semi-empirical methods [6][7][8][9][10][11][12][13][14][15][16] and ab initio methods [17][18][19][20][21][22] have been carried out on these systems. The semi-empirical work was focused both on an analysis of the structural properties of the cyclacenes as well as the behavior of electronic properties such as the HOMO-LUMO gap as a function of the system size parameter n. It was found that the gap decreases in an alternating way depending on the parity of n, as more units are added to the system. Depending on the type of semi-empirical Int J Quantum Chem. 2018;118:e25569.

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Electronic Properties of Cyclacenes from TAO-DFT

Cited by 56 publications

References 60 publications

Effect of Li Termination on the Electronic and Hydrogen Storage Properties of Linear Carbon Chains: A TAO-DFT Study

Effect of Li Termination on the Electronic and Hydrogen Storage Properties of Linear Carbon Chains: A TAO-DFT Study

Role of exact exchange in thermally-assisted-occupation density functional theory: A proposal of new hybrid schemes

A theoretical study on cyclacenes: Analytical tight‐binding approach

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