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Journal articles on the topic 'Time dependent current density functional theory'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Mosquera, Martín A., and Adam Wasserman. "Current density partitioning in time-dependent current density functional theory." Journal of Chemical Physics 140, no. 18 (May 14, 2014): 18A525. http://dx.doi.org/10.1063/1.4867003.

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2

Xu, Bu-Xing, and A. K. Rajagopal. "Current-density-functional theory for time-dependent systems." Physical Review A 31, no. 4 (April 1, 1985): 2682–84. http://dx.doi.org/10.1103/physreva.31.2682.

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3

Kosaka, Keiji. "A Local-Scaling Time-Dependent Current Density Functional Theory." Journal of the Physical Society of Japan 74, no. 10 (October 2005): 2864–65. http://dx.doi.org/10.1143/jpsj.74.2864.

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4

Telnov, Dmitry A., and Shih-I. Chu. "Generalized Floquet formulation of time-dependent current-density-functional theory." Physical Review A 58, no. 6 (December 1, 1998): 4749–56. http://dx.doi.org/10.1103/physreva.58.4749.

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5

Tokatly, I. V. "Time-dependent current density functional theory via time-dependent deformation functional theory: a constrained search formulation in the time domain." Physical Chemistry Chemical Physics 11, no. 22 (2009): 4621. http://dx.doi.org/10.1039/b903666k.

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6

VAN FAASSEN, M. "TIME-DEPENDENT CURRENT-DENSITY-FUNCTIONAL THEORY APPLIED TO ATOMS AND MOLECULES." International Journal of Modern Physics B 20, no. 24 (September 30, 2006): 3419–63. http://dx.doi.org/10.1142/s0217979206035679.

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We review time-dependent current-density-functional theory with the Vignale–Kohn (VK) functional. Historic background and an extensive discussion of the underlying theory is given. In particular, we focus on the application of VK to atoms and (large) molecules in electric fields. Results obtained with VK are shown and the successes and failures of this functional discussed.

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7

Yuen-Zhou, Joel, César Rodríguez-Rosario, and Alán Aspuru-Guzik. "Time-dependent current-density functional theory for generalized open quantum systems." Physical Chemistry Chemical Physics 11, no. 22 (2009): 4509. http://dx.doi.org/10.1039/b903064f.

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8

VIGNALE, G. "TIME-DEPENDENT DENSITY FUNCTIONAL THEORY BEYOND THE ADIABATIC APPROXIMATION." International Journal of Modern Physics B 15, no. 10n11 (May 10, 2001): 1714–23. http://dx.doi.org/10.1142/s0217979201006227.

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I review recent advances in understanding the physical character of the exchange-correlation (xc) potential in time-dependent density functional theory. I show that in an electron gas of slowly varying density the dynamical part of the xc potential is an extremely nonlocal functional of the density. This difficulty can be circumvented by introducing an xc vector potential that is a function of the local current density. The form of this vector potential is entirely specified by symmetry. Its physical effects are analogous to those of the viscous force in the Navier-Stokes equation of classical hydrodynamics. Recent applications of the xc vector potential to the calculation of infrared absorption linewidths in quantum wells are described.

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9

Ullrich, C. A. "Excitation Energies in Time-Dependent (Current-) Density-Functional Theory: A Simple Perspective." Journal of Chemical Theory and Computation 5, no. 4 (February 2, 2009): 859–65. http://dx.doi.org/10.1021/ct800507m.

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10

Escartín, J. M., M. Vincendon, P. Romaniello, P. M. Dinh, P. G. Reinhard, and E. Suraud. "Towards time-dependent current-density-functional theory in the non-linear regime." Journal of Chemical Physics 142, no. 8 (February 28, 2015): 084118. http://dx.doi.org/10.1063/1.4913291.

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11

Yuen-Zhou, Joel, and Alán Aspuru-Guzik. "Remarks on time-dependent [current]-density functional theory for open quantum systems." Physical Chemistry Chemical Physics 15, no. 30 (2013): 12626. http://dx.doi.org/10.1039/c3cp51127h.

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12

Vikas. "Vortex dynamics in the current–density of helium atom evolving in a time-dependent magnetic field: Exchange–correlation functionals of time-dependent current–density functional theory." Chemical Physics Letters 458, no. 1-3 (June 2008): 214–18. http://dx.doi.org/10.1016/j.cplett.2008.04.055.

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13

van Faassen, M., and P. L. de Boeij. "Excitation energies of π-conjugated oligomers within time-dependent current-density-functional theory." Journal of Chemical Physics 121, no. 21 (December 2004): 10707–14. http://dx.doi.org/10.1063/1.1810137.

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14

Harbola, Manoj K., and Arup Banerjee. "Many-Electron Problem in Terms of the Density: From Thomas–Fermi to Modern Density-Functional Theory." Journal of Theoretical and Computational Chemistry 02, no. 02 (June 2003): 301–22. http://dx.doi.org/10.1142/s021963360300046x.

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In this paper we focus on the use of electron density and current-density as basic variables in describing a many-electron system. We start with a discussion of the seminal Thomas–Fermi theory and its extension by Bloch for time-dependent hamiltonians. We then present modern density-functional theory (for both time-independent and time-dependent hamiltonians) and approximations involved in implementing it. Also discussed is perturbation theory in terms of electron density and its use for calculating various response properties and related quantities. In particular, van der Waals coefficient C6 is calculated using density and current density in time-dependent perturbation theory. Throughout the paper, results for alkali-metal clusters are presented to demonstrate the strength of density-based theories.

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15

NAZAROV, V. U., J. M. PITARKE, Y. TAKADA, G. VIGNALE, and Y. C. CHANG. "TIME-DEPENDENT CURRENT-DENSITY FUNCTIONAL THEORY FOR THE FRICTION OF IONS IN AN INTERACTING ELECTRON GAS." International Journal of Modern Physics B 22, no. 22 (September 10, 2008): 3813–39. http://dx.doi.org/10.1142/s0217979208048759.

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Due to the strongly nonlocal nature of fxc(r,r',ω), the scalar exchange and correlation (xc) kernel of the time-dependent density functional theory (TDDFT), the formula for Q the friction coefficient of an interacting electron gas (EG) for ions tends to give too large a value of Q for heavy ions in the medium- and low-density EG, if we adopt the local-density approximation (LDA) to fxc(r, r', ω), even though the formula itself is formally exact. We have rectified this unfavorable feature by reformulating the formula for Q in terms of the tensorialxc kernel of the time-dependent current-density functional theory, to which the LDA can be applied without intrinsic difficulty. Our numerical results find themselves in considerably better agreement with the experimental stopping power of Al and Au for slow ions than those previously obtained within the LDA to the TDDFT.

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16

Gatti, Matteo. "Design of effective kernels for spectroscopy and molecular transport: Time-dependent current–density-functional theory." Journal of Chemical Physics 134, no. 8 (February 28, 2011): 084102. http://dx.doi.org/10.1063/1.3558738.

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17

van Faassen, M., P. L. de Boeij, R. van Leeuwen, J. A. Berger, and J. G. Snijders. "Application of time-dependent current-density-functional theory to nonlocal exchange-correlation effects in polymers." Journal of Chemical Physics 118, no. 3 (January 15, 2003): 1044–53. http://dx.doi.org/10.1063/1.1529679.

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18

Chiofalo, M. L., A. Minguzzi, and M. P. Tosi. "Time-dependent linear response of an inhomogeneous Bose superfluid: microscopic theory and connection to current-density functional theory." Physica B: Condensed Matter 254, no. 3-4 (November 1998): 188–201. http://dx.doi.org/10.1016/s0921-4526(98)00472-4.

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19

van Faassen, M., L. Jensen, J. A. Berger, and P. L. de Boeij. "Size-scaling of the polarizability of tubular fullerenes investigated with time-dependent (current)-density-functional theory." Chemical Physics Letters 395, no. 4-6 (September 2004): 274–78. http://dx.doi.org/10.1016/j.cplett.2004.07.096.

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20

Romaniello, P., and P. L. de Boeij. "Relativistic two-component formulation of time-dependent current-density functional theory: Application to the linear response of solids." Journal of Chemical Physics 127, no. 17 (November 7, 2007): 174111. http://dx.doi.org/10.1063/1.2780146.

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21

Galperin, Michael, and Sergei Tretiak. "Linear optical response of current-carrying molecular junction: A nonequilibrium Green’s function–time-dependent density functional theory approach." Journal of Chemical Physics 128, no. 12 (March 28, 2008): 124705. http://dx.doi.org/10.1063/1.2876011.

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22

Romaniello, P., and P. L. de Boeij. "The role of relativity in the optical response of gold within the time-dependent current-density-functional theory." Journal of Chemical Physics 122, no. 16 (April 22, 2005): 164303. http://dx.doi.org/10.1063/1.1884985.

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23

van Faassen, M., and P. L. de Boeij. "Excitation energies for a benchmark set of molecules obtained within time-dependent current-density functional theory using the Vignale–Kohn functional." Journal of Chemical Physics 120, no. 18 (May 8, 2004): 8353–63. http://dx.doi.org/10.1063/1.1697372.

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24

Flick, Johannes, Michael Ruggenthaler, Heiko Appel, and Angel Rubio. "Kohn–Sham approach to quantum electrodynamical density-functional theory: Exact time-dependent effective potentials in real space." Proceedings of the National Academy of Sciences 112, no. 50 (December 1, 2015): 15285–90. http://dx.doi.org/10.1073/pnas.1518224112.

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The density-functional approach to quantum electrodynamics extends traditional density-functional theory and opens the possibility to describe electron–photon interactions in terms of effective Kohn–Sham potentials. In this work, we numerically construct the exact electron–photon Kohn–Sham potentials for a prototype system that consists of a trapped electron coupled to a quantized electromagnetic mode in an optical high-Q cavity. Although the effective current that acts on the photons is known explicitly, the exact effective potential that describes the forces exerted by the photons on the electrons is obtained from a fixed-point inversion scheme. This procedure allows us to uncover important beyond-mean-field features of the effective potential that mark the breakdown of classical light–matter interactions. We observe peak and step structures in the effective potentials, which can be attributed solely to the quantum nature of light; i.e., they are real-space signatures of the photons. Our findings show how the ubiquitous dipole interaction with a classical electromagnetic field has to be modified in real space to take the quantum nature of the electromagnetic field fully into account.

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25

He, Shenglai, Arthur Russakoff, Yonghui Li, and Kálmán Varga. "Time-dependent density-functional theory simulation of local currents in pristine and single-defect zigzag graphene nanoribbons." Journal of Applied Physics 120, no. 3 (July 21, 2016): 034304. http://dx.doi.org/10.1063/1.4959088.

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26

Li, Yuanzuo, Huixing Li, Peng Song, and Chaofan Sun. "Photoactive Layer of DSSCS Based on Natural Dyes: A Study of Experiment and Theory." Journal of Nanomaterials 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/139382.

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Three natural dyes (Forsythia suspensa, Herba Violae, and Corn leaf) have been investigated as potential sensitizers for dye-sensitized solar cells. UV-vis absorption spectra reveal that three natural dyes mainly contain the compound of pheophytin a. Among three DSSCs, the highest photo electronic conversion efficiencyηis 0.96% with open circuit voltage (VOC) of 0.66 V, short circuit current density (ISC ) of 1.97 mA cm−2, and fill factor (ff) of 0.74. Theoretical time-dependent density functional theory and charge difference density are used to explore the nature of excited states. Results demonstrate that the first state is an intramolecular charge transfer (ICT) state, and electron injection could occur owing to the thermodynamically driving force.

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27

Zhu, Kai-Li, Le-yan Liu, and Zhi-Yuan Geng. "Theoretical study on the structure–property relationship of D–A–π–A-type dye-sensitized solar cells: π-bridge and the side alkyl chain." Canadian Journal of Chemistry 94, no. 9 (September 2016): 794–801. http://dx.doi.org/10.1139/cjc-2016-0156.

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Two series of dyes have been designed and theoretically characterized through density functional theory and time-dependent density functional theory to systematically explore the structure–property relationship of dyes with D–A–π–A architecture and the performance of dye-sensitized solar cells, particularly the influence of the π-bridge, including its alkyl side chain, adding additional conjugate spacer, displacement, and separation of π-bridge. Key parameters associated with the short-circuit current density Jsc and open-circuit photovoltage Voc were characterized and analyzed in detail. All of the analysis results manifest that dye H1 should be the best candidate to fabricate dye-sensitized solar cells owing to the best optical absorption property (a broad absorption band from 300 to 900 nm for adsorbed dye) and other outstanding parameters.

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28

van Faassen, M., and P. L. de Boeij. "Erratum: “Excitation energies for a benchmark set of molecules obtained within time-dependent current-density functional theory using the Vignale–Kohn functional” [J. Chem. Phys.120, 8353 (2004)]." Journal of Chemical Physics 121, no. 14 (October 8, 2004): 7035. http://dx.doi.org/10.1063/1.1794692.

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29

Rashid, Md Al Mamunur, Dini Hayati, Kyungwon Kwak, and Jongin Hong. "Theoretical Investigation of Azobenzene-Based Photochromic Dyes for Dye-Sensitized Solar Cells." Nanomaterials 10, no. 5 (May 9, 2020): 914. http://dx.doi.org/10.3390/nano10050914.

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Two donor-π-spacer-acceptor (D-π-A) organic dyes were designed as photochromic dyes with the same π-spacer and acceptor but different donors, based on their electron-donating strength. Various structural, electronic, and optical properties, chemical reactivity parameters, and certain crucial factors that affect short-circuit current density (Jsc) and open circuit voltage (Voc) were investigated computationally using density functional theory and time-dependent density functional theory. The trans-cis isomerization of these azobenzene-based dyes and its effect on their properties was studied in detail. Furthermore, the dye-(TiO2)9 anatase nanoparticle system was simulated to understand the electronic structure of the interface. Based on the results, we justified how the trans-cis isomerization and different donor groups influence the physical properties as well as the photovoltaic performance of the resultant dye-sensitized solar cells (DSSCs). These theoretical calculations can be used for the rapid screening of promising dyes and their optimization for photochromic DSSCs.

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30

Wang, Dongmei, and Zhiyuan Geng. "Design and characteration of planar star-shaped oligomer electron donors for organic solar cells: a DFT study." Canadian Journal of Chemistry 93, no. 11 (November 2015): 1181–90. http://dx.doi.org/10.1139/cjc-2015-0096.

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To seek high-performance oligomer donor materials used in organic solar cells, four star-shaped molecules with a planar donor core derived from the recent reported molecule 3T-P-DPP (phenyl-1,3,5-trithienyl-diketopyrrolopyrrole) were designed. The molecular properties affecting the cell performance, such as structural characteristics, frontier molecular orbital energy level, absorption spectra, exciton character, and charge transfer/transport, were investigated by means of the density functional theory and time-dependent density functional theory methods. Comparative analysis showed that the new designed molecule 3 with a TTT (2,4,6-tri(thiophen-2-yl)-1,3,5-triazine) core has better planarity, a lower HOMO energy level, and a higher absorption efficiency, as well as more favorable exciton dissociation and charge transfer than the others, potentially improving the open-circuit voltage and short-circuit current density. Consequently, 3 maybe superior to 3T-P-DPP and may act as a promising donor material candidate for organic solar cells.

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31

van Faassen, M., and P. L. de Boeij. "Publisher’s Note: “Excitation energies for a benchmark set of molecules obtained within time-dependent current-density functional theory using the Vignale-Kohn functional” [J. Chem. Phys. 120, 8353 (2004)]." Journal of Chemical Physics 120, no. 24 (June 22, 2004): 11967. http://dx.doi.org/10.1063/1.1762871.

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32

Li, Yuanchao, Lu Mi, Haibin Wang, Yuanzuo Li, and Jianping Liang. "Design, Electron Transfer Process, and Opto-Electronic Property of Solar Cell Using Triphenylamine-Based D-π-A Architectures." Materials 12, no. 1 (January 8, 2019): 193. http://dx.doi.org/10.3390/ma12010193.

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A series of D-π-A type dyes were designed based on the experimentally synthesized A1 by introducing different functional groups on the donor and π-spacer, and the optical and electrical properties were calculated by using density functional theory (DFT) and time-dependent DFT (TD-DFT). P1–P6 present highest light harvesting efficiency (LHE), driving force of electron injection ( Δ G i n j e c t ), reorganization energy ( Δ G r e g ) and e V O C . These critical parameters have a close relationship with the short-circuit current density ( J S C ) and open-circuit photovoltage ( V O C ), and lead to P1–P6 will exhibit higher efficiency. D4 also exhibit superior properties in the driving force of electron injection ( Δ G i n j e c t ), reorganization energy ( Δ G r e g ), which will lead to a higher short-circuit current density ( J S C ). We hope that these results will be helpful for experiments to synthesize new and highly efficient dyes.

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33

Janhunen, P. "On the current-voltage relationship in fluid theory." Annales Geophysicae 17, no. 1 (January 31, 1999): 11–26. http://dx.doi.org/10.1007/s00585-999-0011-y.

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Abstract. The kinetic theory of precipitating electrons with Maxwellian source plasma yields the well-known current-voltage relationship (CV-relationship; Knight formula), which can in most cases be accurately approximated by a reduced linear formula. Our question is whether it is possible to obtain this CV-relationship from fluid theory, and if so, to what extent it is physically equivalent with the more accurate kinetic counterpart. An answer to this question is necessary before trying to understand how one could combine time-dependent and transient phenomena such as Alfvénic waves with a slowly evolving background described by the CV-relationship. We first compute the fluid quantity profiles (density, pressure etc.) along a flux tube based on kinetic theory solution. A parallel potential drop accumulates plasma (and pressure) below it, which explains why the current is linearly proportional to the potential drop in the kinetic theory even though the velocity of the accelerated particles is only proportional to the square root of the accelerating voltage. Electron fluid theory reveals that the kinetic theory results can be reproduced, except for different numerical constants, if and only if the polytropic index γ is equal to three, corresponding to one-dimensional motion. The convective derivative term v·∇v provides the equivalent of the "mirror force" and is therefore important to include in a fluid theory trying to describe a CV-relationship. In one-fluid equations the parallel electric field, at least in its functional form, emerges self-consistently. We find that the electron density enhancement below the potential drop disappears because the magnetospheric ions would be unable to neutralize it, and a square root CV-relationship results, in disagreement with kinetic theory and observations. Also, the potential drop concentrates just above the ionosphere, which is at odds with observations as well. To resolve this puzzle, we show that considering outflowing ionospheric ions restores the possibility of having the acceleration region well above the ionosphere, and thus the electron kinetic (and fluid, if γ=3) theory results are reproduced in a self-consistent manner. Thus the inclusion of ionospheric ions is crucial for a feasible CV-relationship in fluid theory. Constructing a quantitative fluid model (possibly one-fluid) which reproduces this property would be an interesting task for a future study.Key words. Ionosphere (ionosphere-magnetosphere interactions; particle precipitation) · Magnetospheric physics (magnetosphere-ionosphere interactions)

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34

Liu, Qian, Nan Gao, Dejiang Liu, Jinglin Liu, and Yuanzuo Li. "Structure and Photoelectrical Properties of Natural Photoactive Dyes for Solar Cells." Applied Sciences 8, no. 9 (September 19, 2018): 1697. http://dx.doi.org/10.3390/app8091697.

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A series of natural photoactive dyes, named as D1–D6 were successfully extracted from six kinds of plant leaves for solar cells. The photoelectrical properties of dyes were measured via UV-Vis absorption spectra, cyclic voltammetry as well as photovoltaic measurement. To theoretically reveal the experimental phenomena, the chlorophyll was selected as the reference dye, where the ground and excited state properties of chlorophyll were calculated via density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The experimental results show that the absorption peaks of those dyes are mainly distributed in the visible light regions of 400–420 nm and 650–700 nm, which are consistent with the absorption spectrum of chlorophyll. The photoelectrical conversion efficiencies of the solar cells sensitized by the six kinds of natural dyes are in the order of D1 > D4 > D2 > D5 > D6 > D3. The dye D1 performance exhibits the highest photoelectrical conversion efficiency of 1.08% among the investigated six natural dyes, with an open circuit voltage of 0.58 V, a short-circuit current density of 2.64 mA cm−2 and a fill factor of 0.70.

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35

Şener, Sevil. "Ball-Type Dioxy-o-Carborane Bridged Cobaltphthalocyanine: Synthesis, Characterization and DFT Studies For Dye-Sensitized Solar Cells as Photosensitizer." Heterocyclic Communications 26, no. 1 (March 17, 2020): 37–45. http://dx.doi.org/10.1515/hc-2020-0007.

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AbstractThe synthesis and spectroscopic characterization of an innovative ball-type cobalt metallophthalocyanine 4, bridged by four 1,2-bis(2-hydroxymethyl)-O-carborane (HMOC) 1 units, has been achieved. The synthesized compound 4 was characterized structurally and electronically using elemental analysis, UV-Vis absorption spectroscopy, FT-IR spectroscopy, MALDI-TOF mass spectrometry, EPR spectroscopy and magnetic susceptibility. The photovoltaic performance of the newly synthesized compound in dye-sensitized solar cells was investigated. In order to clarify the effect of dye-sensitization time on photovoltaic performance parameters, the sensitization time was varied from 12 to 60 h and the performance parameters were investigated. It was found that sensitization time had a strong effect on the main performance parameters. The best photovoltaic performance was achieved after sensitization for 36 h (short circuit current density, 5.41 mA cm−2; overall conversion efficiency, 3.42%). Computational UV-Vis absorption spectra of the molecule was calculated using time dependent density functional theory and was found consistent with measured UV-Vis spectra.

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36

Smith, Nichola A., and Peter J. Sadler. "Photoactivatable metal complexes: from theory to applications in biotechnology and medicine." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 1995 (July 28, 2013): 20120519. http://dx.doi.org/10.1098/rsta.2012.0519.

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This short review highlights some of the exciting new experimental and theoretical developments in the field of photoactivatable metal complexes and their applications in biotechnology and medicine. The examples chosen are based on some of the presentations at the Royal Society Discussion Meeting in June 2012, many of which are featured in more detail in other articles in this issue. This is a young field. Even the photochemistry of well-known systems such as metal–carbonyl complexes is still being elucidated. Striking are the recent developments in theory and computation (e.g. time-dependent density functional theory) and in ultrafast-pulsed radiation techniques which allow photochemical reactions to be followed and their mechanisms to be revealed on picosecond/nanosecond time scales. Not only do some metal complexes (e.g. those of Ru and Ir) possess favourable emission properties which allow functional imaging of cells and tissues (e.g. DNA interactions), but metal complexes can also provide spatially controlled photorelease of bioactive small molecules (e.g. CO and NO)—a novel strategy for site-directed therapy. This extends to cancer therapy, where metal-based precursors offer the prospect of generating excited-state drugs with new mechanisms of action that complement and augment those of current organic photosensitizers.

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37

Fleming, Scott, Andrew Mills, and Tell Tuttle. "Predicting the UV–vis spectra of oxazine dyes." Beilstein Journal of Organic Chemistry 7 (April 15, 2011): 432–41. http://dx.doi.org/10.3762/bjoc.7.56.

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In the current work we have investigated the ability of time-dependent density functional theory (TD-DFT) to predict the absorption spectra of a series of oxazine dyes and the effect of solvent on the accuracy of these predictions. Based on the results of this study, it is clear that for the series of oxazine dyes an accurate prediction of the excitation energy requires the inclusion of solvent. Implicit solvent included via a polarizable continuum approach was found to be sufficient in reproducing the excitation energies accurately in the majority of cases. Moreover, we found that the SMD solvent model, which is dependent on the full electron density of the solute without partitioning into partial charges, gave more reliable results for our systems relative to the conductor-like polarizable continuum model (CPCM), as implemented in Gaussian 09. In all cases the inclusion of solvent reduces the error in the predicted excitation energy to <0.3 eV and in the majority of cases to <0.1 eV.

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38

Kudisch, Bryan, Margherita Maiuri, Luca Moretti, Maria B. Oviedo, Leon Wang, Daniel G. Oblinsky, Robert K. Prud’homme, Bryan M. Wong, Stephen A. McGill, and Gregory D. Scholes. "Ring currents modulate optoelectronic properties of aromatic chromophores at 25 T." Proceedings of the National Academy of Sciences 117, no. 21 (May 8, 2020): 11289–98. http://dx.doi.org/10.1073/pnas.1918148117.

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The properties of organic molecules can be influenced by magnetic fields, and these magnetic field effects are diverse. They range from inducing nuclear Zeeman splitting for structural determination in NMR spectroscopy to polaron Zeeman splitting organic spintronics and organic magnetoresistance. A pervasive magnetic field effect on an aromatic molecule is the aromatic ring current, which can be thought of as an induction of a circular current of π-electrons upon the application of a magnetic field perpendicular to the π-system of the molecule. While in NMR spectroscopy the effects of ring currents on the chemical shifts of nearby protons are relatively well understood, and even predictable, the consequences of these modified electronic states on the spectroscopy of molecules has remained unknown. In this work, we find that photophysical properties of model phthalocyanine compounds and their aggregates display clear magnetic field dependences up to 25 T, with the aggregates showing more drastic magnetic field sensitivities depending on the intermolecular interactions with the amplification of ring currents in stacked aggregates. These observations are consistent with ring currents measured in NMR spectroscopy and simulated in time-dependent density functional theory calculations of magnetic field-dependent phthalocyanine monomer and dimer absorption spectra. We propose that ring currents in organic semiconductors, which commonly comprise aromatic moieties, may present new opportunities for the understanding and exploitation of combined optical, electronic, and magnetic properties.

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39

Liu, Qian, Penghui Ren, Xiaofei Wang, Yuanzuo Li, and Yanhui Yang. "Experimental and Theoretical Investigation of the Photoelectrical Properties of Tetrabromophenol Blue- and Bromoxylenol Blue-Based Solar Cells." Journal of Nanomaterials 2018 (July 22, 2018): 1–13. http://dx.doi.org/10.1155/2018/9720595.

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Tetrabromophenol blue and Bromoxylenol blue as the sensitizers of dye-sensitized solar cells (DSSCs) are measured in experiments. In order to better understand the photoelectrical properties of the two dyes, we obtain the UV-Vis spectra, fluorescence spectra, and current-voltage characteristics. The frontier molecular orbital, energy levels, the first hyperpolarizability, the first hyperpolarizability density, and molecular electrostatic potential are calculated with density functional theory (DFT) and time-dependent DFT (TDDFT). The critical factors including the light harvesting efficiency (LHE (Tetrabromophenol blue for 0.0284 and Bromoxylenol blue for 0.0290), the driving force of electron injection (ΔGinject), x-axis direction dipole moment (μnormal), the conduction band of edge of the semiconductor (ΔECB), and the excited-state lifetime (τ)) are computed, which have a close connection to the short-circuit current density (Jsc) and open-circuit voltage (Voc). The results show that the Jsc (0.09 mA/cm2) and Voc (0.39 V) of Tetrabromophenol blue have larger values, which can be explained by a larger absolute value of ΔGinject, absolute value of μnormal, τ, and ΔECB. Therefore, Tetrabromophenol blue displays well photoelectric conversion efficiency compared with Bromoxylenol blue.

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40

Ghafoor, Sidra, Asim Mansha, Sadia Asim, Muhammad Usman, Ameer Fawad Zahoor, and Hafiz Saqib Ali. "The structural, spectral, frontier molecular orbital and thermodynamic analysis of 2-hydroxy 2-methyl propiophenone by MP2 and B3LYP methods." Journal of Theoretical and Computational Chemistry 19, no. 05 (July 31, 2020): 2050020. http://dx.doi.org/10.1142/s0219633620500200.

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In the present work, we have studied the 2-hydroxy 2-methyl propiophenone (2H2MPP) theoretically as well as experimentally. The optimized molecular structure has been obtained by the density functional theory (DFT), second-order Moller–Plesset perturbation theory (MP2) and Hartree Fock (HF) in the gas phase as well as in different media like ethanol, DMSO and heptane. FT-IR and FT-Raman spectra were computed as well as recorded and fundamental vibrational wavenumbers were assigned. The electronic absorption spectra were calculated by employing the time-dependent density functional theory (TD-DFT) to get the information about excitation energies, oscillator strength and excited state geometries in gas phase and in different solvent media. Chemical activity and chemical stability obtained by HOMO-LUMO studies using a HF/6-31[Formula: see text]G and MP2/6-311[Formula: see text]G calculations. The chemical interpretation of hyperconjugation interactions obtained by the Natural Bond Orbital (NBO) analysis. Moreover, electrostatic potential (ESP) calculations performed to get the visual representation of relative polarity of molecule. Thermodynamic parameters like enthalpy, entropy, heat capacity, and Gibbs free energy computed with varying temperature from 10[Formula: see text]K to 500[Formula: see text]K. The aim of the current investigation is to find out the quantum chemical properties of the title compound which show an active role in the pharmaceutical and printing industries.

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41

Zhao, Dongpeng, Qiuchen Lu, Runzhou Su, Yuanzuo Li, and Meiyu Zhao. "Light Harvesting and Optical-Electronic Properties of Two Quercitin and Rutin Natural Dyes." Applied Sciences 9, no. 12 (June 24, 2019): 2567. http://dx.doi.org/10.3390/app9122567.

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The photovoltaic properties of two dyes (quercitin (Q) and rutin (R)) were experimentally investigated. The results showed that Q had excellent photoelectric properties with J s c of 5.480 mA·cm−2, V o c of 0.582 V, η of 2.151% larger than R with J s c of 1.826 mA·cm−2, V o c of 0.547 V, and η of 0.713%. For a better understanding of the photoelectric properties of two molecules and illustrating why the performances of Q is better than R from the micro-level, the UV-VIs spectrum, Fourier transforms infrared (FT-IR) spectrum, and cyclic voltage current characteristics were experimentally investigated. What is more, density functional theory (DFT) and time dependent density functional theory (TD-DFT) have been implemented in theoretical calculation. Based on the calculated results, frontier molecular orbitals (FMOs), charge differential density (CDD), infrared vibration, first hyperpolarizability, projected density orbital analysis (PDOS), electrostatic potential (ESP), and natural bond orbital (NBO) were analyzed. Hole/electron reorganization energies ( λ h / λ e ), light harvesting efficiency (LHE), fluorescent lifetime (τ), absorption peak, and the vertical dipole moment ( μ n o r m a l ) were calculated, and the shift of conduction band edge of a semiconductor (ΔECB) has been analyzed, which has a close relationship with J s c and V o c . The results demonstrated that, due to the higher LHE, τ, μ n o r m a l , and red-shifted absorption peak, Q has better photoelectric properties than R as a promising sensitizer.

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42

Molla, Fadime, Ayşegül Yazıcı, Nursel Acar Selçuki, Ahmet Altındal, Bekir Salih, and Özer Bekaroğlu. "Synthesis, characterization, OFET, and DFT study of the novel ball-type metallophthalocyanines bridged with four diaminopyrimidine-dithiol." Journal of Porphyrins and Phthalocyanines 24, no. 05n07 (May 2020): 662–74. http://dx.doi.org/10.1142/s1088424619501190.

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Co2Pc2 (2) and Zn2Pc2 (3) were obtained in DMF and LuPc2 (4) was obtained in hexanol by the cyclotetramerization of novel diphthalonitrile (1). Synthesized compounds were characterized by FT-IR, 1H-NMR, elemental analyses, MALDI-TOF MS and UV-vis spectroscopy techniques. Optimized geometries and electronic structures for compounds 2, 3 and 4 were investigated by Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT). In compound 2, a new bond was observed between Co centers forming two Co(III) with the interaction of d orbitals. Computational and experimental UV-vis spectra in DMF were found in agreement for the investigated compounds. Vertical and adiabatic ionization potentials for the studied systems were also calculated. The gate dielectric performances of thin films obtained from these compounds were investigated by fabricating ITO/2–4/Au devices. The observed reverse bias J-V characteristics revealed that the leakage current in ITO/2–4/Au devices is because of the Poole–Frenkel effect. The effect of the gate dielectric on the OFET performance parameters was also investigated by fabricating bottom-gate top-contact OFET using pentacene as the active layer. Maximum field effect mobility was observed with the 2-based OFET device. Calculated HOMO–LUMO gap, hole reorganization energy and ionization energy have also supported the experimental results which indicate that 2 is the most suitable system for OFET devices.

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Dheivamalar, S., and K. Bansura banu. "Enhancing the Light Harvesting Efficiency, Open Circuit Voltage And Stability of Molybdenum Doped (Zno)6 Nanocluster in Dye-Sensitized Solar Cells: A DFT Study." Oriental Journal of Chemistry 34, no. 5 (October 18, 2018): 2292–304. http://dx.doi.org/10.13005/ojc/340509.

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In this study, the electronic and structural properties of drum structured Mo-doped Zn6O6 (MoZn5O6) cluster as the π conjugated bridging in the dye-sensitized solar cells (DSSC) were compared with its pristine form by density functional theory (DFT) calculations under Gaussian 09 Program. The frontier molecular orbital study was explored to determine the charge transport characteristics of donor-acceptor moieties over the entire visible range and the electron injection from the valence band (LUMO) orbital to the conduction band (HOMO) orbital of MoZn5O6. The energy gap (Eg), binding energy (EB), global reactivity descriptors, thermodynamic parameters and the dipole moment were also calculated for MoZn5O6 and compared with Zn6O6. The density of states (DOS) of MoZn5O6 material was investigated to demonstrate the importance of d orbital of Mo atom in hybridization. To examine the charge distribution, Mulliken atomic charge distribution and molecular electrostatic potential (MEP) were analyzed. A spectroscopic study was included for the better perception of the interaction of Mo with Zn6O6 cluster. The increased value of the first-order hyperpolarizability of MoZn5O6 from its pure clustermanifests the MoZn5O6 is a better candidate with the superior nonlinear optical property. The analysis of UV-Vis spectra through the time-dependent density functional theory (TD-DFT) discovers that the MoZn5O6 has larger light harvesting efficiency (LHE) which influences the higher photon to current conversion efficiency. As a result, the valence band (LUMO) of MoZn5O6 is intense than the conduction band (HOMO) of MoZn5O6 making an increase in the open circuit voltage (VOC) and hence it confirms that the MoZn5O6 material can be a used in photovoltaic applications.

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44

Xu, Zhijie, Xiaoqing Lu, Yuanyuan Li, and Shuxian Wei. "Theoretical Analysis on Heteroleptic Cu(I)-Based Complexes for Dye-Sensitized Solar Cells: Effect of Anchors on Electronic Structure, Spectrum, Excitation, and Intramolecular and Interfacial Electron Transfer." Molecules 25, no. 16 (August 12, 2020): 3681. http://dx.doi.org/10.3390/molecules25163681.

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Two groups of heteroleptic Cu(I)-based dyes were designed and theoretically investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. Different anchors were integrated into the dye skeleton to shed light on how the type of anchor influenced the electronic structure, absorption spectrum, electron excitation, and intramolecular and interfacial electron transfer of dyes. The results indicated that, compared with other dyes, the dyes with cyanoacrylic acid and nitric acid exhibited more appropriate electron distributions in frontier molecular orbitals (FMOs), lower HOMO (the highest occupied molecular orbital) –LUMO (the lowest unoccupied molecular orbital) energy gaps, broader absorption spectral ranges as well as improved spectral characteristics in the near-infrared region and better intramolecular electron transfer (IET) characteristics with more electrons transferred to longer distances, but smaller orbital overlap. Among all the studied Cu(I)-based dyes, B1 and P1 (with cyanoacrylic acid anchoring group) exhibited the best interface electronic structure parameters with a relatively short electron injection time (τinj) and large dipole moment (μnormal), which would have a positive effect on the open-circuit photovoltage (Voc) and short-circuit current density (Jsc), resulting in high power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). Our findings are expected to provide a new insight into the designing and screening of high-performance dyes for DSSCs.

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45

Rizzo, Antonio, Dmitry Shcherbin, and Kenneth Ruud. "Jones and magnetoelectric birefringence of pure substances — A computational study." Canadian Journal of Chemistry 87, no. 10 (October 2009): 1352–61. http://dx.doi.org/10.1139/v09-087.

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We present the first investigation of condensed-phase effects on the Jones (and magnetoelectric) birefringence of a set of nondipolar (CCl4 and CS2) and dipolar (nitro- and chloro-benzene) molecules using a recent implementation of the polarizable continuum model for cubic response functions at the time-dependent density-functional level of theory. The condensed-phase calculations have been performed on the neat liquids of the sample molecules using a nonequilibrium solvation scheme to properly account for the solute–solvent interactions in the presence of a frequency-dependent electromagnetic field. It is demonstrated that the condensed-phase effects as modelled by the polarizable continuum model can be substantial, increasing the observable birefringence by more than sixty percent in the case of CCl4, and by a factor of more than three for CS2. Solvent effects are also substantial for the dipolar molecules, leading to an enhancement by a factor of roughly five for nitrobenzene and by a bit less than 30% for chlorobenzene. Comparison is made with the results of experiment. Our calculated anisotropies confirm that the effect is below current experimental detection limits for CCl4 and CS2. We compute Jones constants of the same order of magnitude as the upper limits given in experiment for nitro- and chlorobenzene.

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46

Marques, M. A. L., and E. K. U. Gross. "TIME-DEPENDENT DENSITY FUNCTIONAL THEORY." Annual Review of Physical Chemistry 55, no. 1 (June 2004): 427–55. http://dx.doi.org/10.1146/annurev.physchem.55.091602.094449.

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47

Oprea, Corneliu I., Petre Panait, Zahraa M. Essam, Reda M. Abd El-Aal, and Mihai A. Gîrțu. "Photoexcitation Processes in Oligomethine Cyanine Dyes for Dye-Sensitized Solar Cells—Synthesis and Computational Study." Nanomaterials 10, no. 4 (April 2, 2020): 662. http://dx.doi.org/10.3390/nano10040662.

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We report density functional theory (DFT) calculations of three newly synthesized oligomethine cyanine-based dyes as potential TiO2-sensitizers in dye-sensitized solar cells. The three dyes have π-symmetry and the same acceptor side, terminating in the carboxylic anchor, but they differ through the π-bridge and the donor groups. We perform DFT and time-dependent DFT studies and present the electronic structure and optical properties of the dyes alone as well as adsorbed to the TiO2 nanocluster, to provide some predictions on the photovoltaic performance of the system. We analyze theoretically the factors that can influence the short circuit current and the open circuit voltage of the dye-sensitized solar cells. We examine the matching of the absorption spectra of the dye and dye-nanocluster system with the solar irradiation spectrum. We display the energy level diagrams and discuss the alignment between the excited state of the dyes and the conduction band edge of the oxide as well as between the redox level of the electrolyte and the ground state of the dyes. We determine the electron density of the key molecular orbitals and analyze comparatively the electron transfer from the dye to the semiconducting substrate. To put our findings in the right perspective we compare the results of our calculations with those obtained for a coumarin-based dye used in fabricating and testing actual devices, for which experimental data regarding the photovoltaic performance are available.

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48

Niehaus, T. A. "Approximate time-dependent density functional theory." Journal of Molecular Structure: THEOCHEM 914, no. 1-3 (November 2009): 38–49. http://dx.doi.org/10.1016/j.theochem.2009.04.034.

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Munakata, Toyonori. "Time-dependent density-functional theory withHtheorems." Physical Review E 50, no. 3 (September 1, 1994): 2347–50. http://dx.doi.org/10.1103/physreve.50.2347.

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Ko, Chaehyuk, David K. Malick, Dale A. Braden, Richard A. Friesner, and Todd J. Martínez. "Pseudospectral time-dependent density functional theory." Journal of Chemical Physics 128, no. 10 (March 14, 2008): 104103. http://dx.doi.org/10.1063/1.2834222.

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