scholarly journals On the origin of nonlocal damping in plasmonic monomers and dimers

2017 ◽  
Vol 31 (24) ◽  
pp. 1740005 ◽  
Author(s):  
Christos Tserkezis ◽  
Wei Yan ◽  
Wenting Hsieh ◽  
Greg Sun ◽  
Jacob B. Khurgin ◽  
...  
Keyword(s):  
Density Functional ◽  
Electron Tunneling ◽  
Circuit Modeling ◽  
Spherical Nanoparticles ◽  
Electron Hole ◽  
Functional Theory ◽  
Tddft Calculations ◽  
Equivalent Circuit Modeling ◽  
Dielectric Interfaces ◽  
Mechanical Studies

The origin and importance of nonlocal damping is discussed through simulations with the generalized nonlocal optical response (GNOR) theory, in conjunction with time-dependent density functional theory (TDDFT) calculations and equivalent circuit modeling, for some of the most typical plasmonic architectures: metal–dielectric interfaces, metal–dielectric–metal gaps, spherical nanoparticles and nanoparticle dimers. It is shown that diffusive damping, as introduced by the convective–diffusive GNOR theory, describes well the enhanced losses and plasmon broadening predicted by ab initio calculations in few-nm particles or few-to-sub-nm gaps. Through the evaluation of a local effective dielectric function, it is shown that absorptive losses appear dominantly close to the metal surface, in agreement with TDDFT and the mechanism of Landau damping due to generation of electron–hole pairs near the interface. Diffusive nonlocal theories provide therefore an efficient means to tackle plasmon damping when electron tunneling can be safely disregarded, without the need to resort to more accurate, but time-consuming fully quantum-mechanical studies.

How big is big? Separation by conventional methods, X-ray and electronic structures of positional isomers of bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato iron(II) complex

2016 ◽  
Vol 20 (01n04) ◽  
pp. 337-351 ◽  
Author(s):  
Derrick R. Anderson ◽  
Pavlo V. Solntsev ◽  
Hannah M. Rhoda ◽  
Victor N. Nemykin
Keyword(s):  
Electronic Structures ◽  
Density Functional ◽  
Positional Isomers ◽  
Excitation Energies ◽  
Functional Theory ◽  
X Ray ◽  
Vertical Excitation ◽  
X Ray Crystallography ◽  
Tddft Calculations ◽  
Insight Into

A presence of bulky 2,6-di-iso-propylphenoxy groups in bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato iron(II) complex allows separation of two individual positional isomers and a mixture of the remaining two isomers using conventional chromatography. X-ray structures of “[Formula: see text]” and “[Formula: see text]” isomers were confimed by X-ray crystallography. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations of each individual positional isomer allowed insight into their electronic structures and vertical excitation energies, which were correlated with the experimental UV-vis and MCD spectra.

scholarly journals Analysis and visualization of energy densities. II. Insights from linear-response time-dependent density functional theory calculations

2020 ◽  
Vol 22 (46) ◽  
pp. 26852-26864 ◽  
Author(s):  
Zheng Pei ◽  
Junjie Yang ◽  
Jingheng Deng ◽  
Yuezhi Mao ◽  
Qin Wu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Response Time ◽  
Linear Response ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Tddft Calculations ◽  
Density Analysis ◽  
Dependent Density

Inspired by the analysis of Kohn–Sham energy densities by Nakai and coworkers, we extended the energy density analysis to linear-response time-dependent density functional theory (LR-TDDFT) calculations.

Predicting phosphorescent lifetimes and zero-field splitting of organometallic complexes with time-dependent density functional theory including spin–orbit coupling

2014 ◽  
Vol 16 (28) ◽  
pp. 14523-14530 ◽  
Author(s):  
K. Mori ◽  
T. P. M. Goumans ◽  
E. van Lenthe ◽  
F. Wang
Keyword(s):  
Density Functional ◽  
Organometallic Complexes ◽  
Orbit Coupling ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Zero Field Splitting ◽  
Solvation Model ◽  
Functional Theory ◽  
Tddft Calculations

Experimental phosphorescent lifetimes for various organometallic complexes are well reproduced by spin–orbit coupling TDDFT calculations with a continuum solvation model.

First-principles study on codoping effect to enhance photocatalytic activity of anatase TiO2

2017 ◽  
Vol 31 (06) ◽  
pp. 1750036
Author(s):  
Yujie Bai ◽  
Qinfang Zhang ◽  
Fubao Zheng ◽  
Yun Yang ◽  
Qiangqiang Meng ◽  
...  
Keyword(s):  
Visible Light ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
Band Edge ◽  
Electron Hole ◽  
Functional Theory ◽  
Rich Condition

Codopant is an effective approach to modify the bandgap and band edge positions of transition metal oxide. Here, the electronic structures as well as the optical properties of pristine, mono-doped (N/P/Sb) and codoped (Sb, N/P) anatase TiO2 have been systematically investigated based on density functional theory calculations. It is found that mono-doped TiO2 exhibits either unoccupied or partially occupied intermediate state within the energy gap, which promotes the recombination of electron-hole pairs. However, the presence of (Sb, N/P) codopant not only effectively reduces the width of bandgap by introducing delocalized occupied intermediate states, but also adjusts the band edge alignment to enhance the hydrogen evolution activity of TiO2. Moreover, the optical absorption spectrum for (Sb, N/P) codoped TiO2, which is favored under oxygen-rich condition, demonstrates the improvement of its visible light absorption. These findings will promote the potential application of (Sb, N/P) codoped TiO2 photocatalysis for water splitting under visible light irradiation.

scholarly journals A Theoretical Evaluation of the Efficiencies of Metal-Free 1,3,4-Oxadiazole Dye-Sensitized Solar Cells: Insights From Electron-Hole Separation Distance Analysis.

2021 ◽  
Author(s):  
Louis-Charl Coetzee ◽  
Adedapo Adeyinka ◽  
Nomampondo Magwa
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Density Functional ◽  
Dye Sensitized Solar Cells ◽  
Separation Distance ◽  
Electron Hole ◽  
Functional Theory ◽  
Metal Free ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Abstract Herein, some novel metal-free 1,3,4-oxadiazole compounds O1-O7 were evaluated for Photovoltaic properties using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations to determine if they can serve as metal-free organic dyes for the use of dye-sensitized solar cells (DSSCs). To understand the trends in the relative efficiencies of the investigated compounds as dyes in DSSCs, their electron contributions, hole contributions, and electron-hole overlaps for each respective atom and fragment within the molecule were analyzed with a particular focus on the electron densities on the anchoring segments. As transition density matrices (TDM) provide details for the departure of each electron from its corresponding hole during excitations, which results in charge transfer (CT), the charge separation distance (Δr) between the electron and its corresponding hole was studied as well as the degree of electron-hole overlap (Ʌ). The latter, single-point excitation energy of each electron, the percentage electron contribution to the anchoring segments of each compound, the incident-photon-conversion-efficiency (IPCE), charge recombination, light harvesting efficiency (LHE) electron injection (Φinj) and charge collection efficiency (ncollect) were then compared to Δr to determine whether the expected relationships hold. Moreover, parameters such as diffusion constant (Dπ) and electron lifetime (t), amongst others, were also used to describe electron excitation processes. Since IPCE is the key parameter in determining the efficiency, O3 was found to be the best dye due to its highest value.

scholarly journals First Principles Study on Electronic and Optical Properties of Quinary Copper-based Sulfides and Selenides Cu2HgGe(S1-xSex)4

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Pham Dinh Khang ◽  
Vo Duy Dat ◽  
Dang Phuc Toan ◽  
Vu Van Tuan
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Hybrid Functional ◽  
Electron Hole ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Pair Separation ◽  
Electron Hole Pair ◽  
Band Transition

Electronic and optical properties of Cu2HgGe(S1-xSex)4 compounds (x = 0, 0.25, 0.5, 0.75, and 1) were revealed by density functional theory (DFT), in which the Heyd-Scuseria-Ernzerhof hybrid functional was used. Dependence of band gap on the Se constituent in Cu2HgGe(S1-xSex)4 was reported. The substitution of Se element basically cause a slightly lattice expansion and minor change of the band gap. Meanwhile, the overlap of Cu and S/Se states becomes more dense leading to better electron/hole pair separation and inter-band transition of photo-excited electrons. The Cu2HgGe(S0.75Se0.25)4 compound was predicted to be very promising absorber due to the low band gap, high absorption rate, and low reflectivity in the incoming light energy range from 0 eV to 2 eV.    

scholarly journals Synthesis and TDDFT Investigation of New Maleimide Derivatives Bearing Pyrrole and Indole Ring

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Yasuhiro Shigemitsu ◽  
Kaori Komiya ◽  
Naoko Mizuyama ◽  
Masayori Hagimori ◽  
Yoshinori Tominaga
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Condensation Reaction ◽  
Time Dependent ◽  
Indole Ring ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Tddft Calculations ◽  
Temperature Time ◽  
Dependent Density

A novel series of heterocycles were obtained through the condensation reaction of 4-methylthiomaleimides with pyrroles and indoles. The newly synthesized compounds exhibit their major electronic absorption peaks ranging 435–504 nm in solution at room temperature. Time-dependent density-functional theory (TDDFT) calculations were systematically performed in order to elucidate their structure-color relationships, using a set of exchange-correlation (XC) functionals. The TDDFT computational scheme employing PCM-TDDFT/6-31+G(d,p)//DFT/6-311G(d,p) level of theory gave qualitatively satisfactory results in their predictions.

scholarly journals Strong Valence Electrons Dependent and Logical Relations of Elemental Impurities in 2D Binary Semiconductor: a Case of GeP3 Monolayer from Ab Initio Studies

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Suihao Zhang ◽  
Rui Li ◽  
Xiaonan Fu ◽  
Yu Zhao ◽  
Chunyao Niu ◽  
...  
Keyword(s):  
Density Functional ◽  
Logical Relation ◽  
Comprehensive Understanding ◽  
Electron Hole ◽  
Functional Theory ◽  
Group Iii ◽  
Co Doping ◽  
Elemental Impurities ◽  
Valence Electrons ◽  
Co Doped

Abstract Using first-principle calculations within density functional theory, we investigate the electronic property and stability of substitutionally doped 2D GeP3 monolayer with dopants from group III to VI. The conducting properties are found to be dramatically modified by both the doping sites and the number of valence electrons of dopants. Specifically, substitution on Ge site exhibits metal-semiconductor oscillations as a function of the number of valence electrons of dopants, while such oscillations are totally reversed when substitution on P site. Moreover, we also study the case of co-doping in GeP3, showing that co-doping can produce a logical “AND” phenomenon, that is, the conducting properties of co-doped GeP3 can be deduced via a simple logical relation according to the results of single doping. Finally, we investigate the formation energy of dopants and find that the electron-hole and hole-hole co-doped systems are much more energetically favorable due to the Coulomb attraction. Our findings not only present a comprehensive understanding of 2D doping phenomenon, but also propose an intriguing route to tune the electronic properties of 2D binary semiconductors.

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