Electronic structure of rhombus-shaped nanographenes: system size evolution from closed- to open-shell ground states

Sandoval‐Salinas, María Eugenia; Bernabeu-Cabañero, Raúl M.; Pérez-Jiménez, Ángel J.; San‐Fabián, Emilio; Sancho-García, Juan-Carlos

doi:10.1039/d3cp01103h

Cited by 7 publications

(4 citation statements)

References 92 publications

(122 reference statements)

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“…For example, for the GS properties of physical systems at θ el = 0, FT-DFT with F [26,38,41]. Therefore, a number of recent studies on the GS properties of physical systems at θ el = 0 [74][75][76][77][78][79][80][81] have actually been performed using TAO-DFT with…”

Section: Tao-dft (Withmentioning

confidence: 99%

Real-Time Extension of TAO-DFT

Tsai,

Chai

2023

Molecules

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Thermally assisted occupation density functional theory (TAO-DFT) has been an efficient electronic structure method for studying the ground-state properties of large electronic systems with multi-reference character over the past few years. To explore the time-dependent (TD) properties of electronic systems (e.g., subject to an intense laser pulse), in this work, we propose a real-time (RT) extension of TAO-DFT, denoted as RT-TAO-DFT. Moreover, we employ RT-TAO-DFT to study the high-order harmonic generation (HHG) spectra and related TD properties of molecular hydrogen H2 at the equilibrium and stretched geometries, aligned along the polarization of an intense linearly polarized laser pulse. The TD properties obtained with RT-TAO-DFT are compared with those obtained with the widely used time-dependent Kohn–Sham (TDKS) method. In addition, issues related to the possible spin-symmetry breaking effects in the TD properties are discussed.

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Section: Tao-dft (Withmentioning

confidence: 99%

Real-Time Extension of TAO-DFT

Tsai,

Chai

2023

Molecules

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“…Over the last few years, TAO-DFT has been employed to explore the electronic [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61], hydrogen storage [47,49,50], and spectroscopic [43,62,63] properties of gas-phase nanomolecules with MR character, outperforming KS-DFT with the widely used XC energy functionals. Moreover, a few recent studies [64][65][66][67] on the ground-state properties of electronic systems at absolute zero have been actually performed using an approximate TAO-DFT method (i.e., TAO-DFT without the θ-dependent energy functional [37]) at some fictitious temperature θ, which should not be confused with the Mermin-Kohn-Sham method (also called finite-temperature density functional theory (FT-DFT)) [23,68] at some finite electronic temperature due to their distinctly different physical meanings (e.g., see Refs. [37,44,58] for further discussion).…”

Section: Of 18mentioning

confidence: 99%

TAO-DFT with the Polarizable Continuum Model

Seenithurai¹,

Chai²

2023

Preprint

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For the ground-state properties of gas-phase nanomolecules with multi-reference character, thermally-assisted-occupation density functional theory (TAO-DFT) has been recently found to outperform the widely used Kohn-Sham density functional theory, when the conventional exchange-correlation energy functionals are employed. Aiming to explore solvation effects on the ground-state properties of nanomolecules with multi-reference character at a minimal computational cost, we combine TAO-DFT with the polarizable continuum model (PCM). To show its usefulness, TAO-DFT-based PCM (TAO-PCM) is employed to study the electronic properties of linear acenes in three different solvents (toluene, chlorobenzene, and water). According to TAO-PCM, in the presence of these solvents, the smaller acenes should have nonradical nature, and the larger acenes should have increasing polyradical nature, showing remarkable similarities to the past findings in the gas phase.

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“…On the computational side, Omist et al [ 26 ] reported the electronic properties of GNP[2, n ] (with n = 3–7) and nitrogen-doped GNP[2, n ], obtained with various electronic structure methods. Besides, Sandoval-Salinas et al [ 27 ] performed electronic structure calculations to explore the electronic properties of GNP[ m , n ] (with

= 2–6). In addition, a recent computational study reported a few electronic properties of GNP[ m , n ] (with

= 2–4) [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Electronic Properties of Graphene Nano-Parallelograms: A Thermally Assisted Occupation DFT Computational Study

Seenithurai,

Chai

2024

Molecules

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In this computational study, we investigate the electronic properties of zigzag graphene nano-parallelograms (GNPs), which are parallelogram-shaped graphene nanoribbons of various widths and lengths, using thermally assisted occupation density functional theory (TAO-DFT). Our calculations revealed a monotonic decrease in the singlet–triplet energy gap as the GNP length increased. The GNPs possessed singlet ground states for all the cases examined. With the increase of GNP length, the vertical ionization potential and fundamental gap decreased monotonically, while the vertical electron affinity increased monotonically. Some of the GNPs studied were found to possess fundamental gaps in the range of 1–3 eV, lying in the ideal region relevant to solar energy applications. Besides, as the GNP length increased, the symmetrized von Neumann entropy increased monotonically, denoting an increase in the degree of the multi-reference character associated with the ground state GNPs. The occupation numbers and real-space representation of active orbitals indicated that there was a transition from the nonradical nature of the shorter GNPs to the increasing polyradical nature of the longer GNPs. In addition, the edge/corner localization of the active orbitals was found for the wider and longer GNPs.

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Electronic structure of rhombus-shaped nanographenes: system size evolution from closed- to open-shell ground states

Abstract: We theoretically study and characterize a set of rombus-shaped nanographenes of increasing size, or n-rhombenes, where n = 2−6, displaying zigzag edges leading to an enhancement of the (poly)radicaloid nature...

Cited by 7 publications

References 92 publications

Real-Time Extension of TAO-DFT

Real-Time Extension of TAO-DFT

TAO-DFT with the Polarizable Continuum Model

Electronic Properties of Graphene Nano-Parallelograms: A Thermally Assisted Occupation DFT Computational Study

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