Application of the method of moments to the study of the electronic spectra of organic dyes

Dyadyusha, G. G.; Ishchenko, A. A.

doi:10.1007/bf00615763

Cited by 13 publications

(12 citation statements)

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“…36,37 Here ν ̅ corresponds more exactly the energy of vertical transition than the absorption maximum does, while σ allows a more objective comparison of spectral bandwidth with different shapes than the full width at half maximum (FWHM). 35 Besides the phenomenon of solvatochromic reversal, the analysis clearly indicates that replacing the TCF with FP-TCF can lead to the different reduction of ν ̅ in the absorption bands of chromophores, by ∼800 cm −1 in 1,4dioxane of low polarity and ∼1000 cm −1 in acetonitrile of high polarity. The shift of absorption bands is accompanied by the reduced σ, which again is highly dependent on the E T N value of solvents.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

“…The long-wavelength absorption bands of F3 -series chromophores were quantitatively analyzed by the method of moments to calculate the mean wave number (ν̅) of the photons and the width of the spectral curve (σ), according to the convention reported by Ishchenko, Kulinich, and their colleagues. ,, The results were further plotted against the normalized solvent polarity parameter E T N (Tables S2, S3, and Figure S9). , Here ν̅ corresponds more exactly the energy of vertical transition than the absorption maximum does, while σ allows a more objective comparison of spectral bandwidth with different shapes than the full width at half maximum (FWHM) . Besides the phenomenon of solvatochromic reversal, the analysis clearly indicates that replacing the TCF with FP-TCF can lead to the different reduction of ν̅ in the absorption bands of chromophores, by ∼800 cm –1 in 1,4-dioxane of low polarity and ∼1000 cm –1 in acetonitrile of high polarity.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The UV– vis –NIR spectra of chromophores were recorded with an ultra-violet visible scanning spectrophotometer (Shimadzu 1700) and an ultra-violet visible near-infrared spectrophotometer with integrating sphere (PE Lamda 750). The long-wavelength absorption bands of F3 -series chromophores were quantitatively analyzed by the method of moments to calculate the mean wave number of the photons and the width of the spectral curve. ,, DFT calculations using Gaussian 09 package were carried out at the level of B3LYP/6-31G(d,p) for ground-state geometry optimization.…”

Section: Methodsmentioning

confidence: 99%

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Efficient, Stable, and Scalable Push–Pull Heptamethines for Electro-Optics

Zhang

Zou

et al. 2022

Chem. Mater.

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Currently, there is increasing interest in the use of push–pull heptamethine chromophores containing the 2-dicyanomethylidene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF) electron acceptor for electro-optic (EO) applications. Compared with the benchmark push–pull tetraenes with a stronger trifluoromethyl-substituted TCF acceptor (CF3-TCF), the TCF-based push–pull heptamethines showed lower EO activities; however, they have better chemical and thermal stability and higher synthetic efficacy. Herein we report the facile synthesis and analysis of structure–property relationship of dipolar heptamethines containing a strong electron acceptor, bis(4-fluorophenyl)-substituted TCF (FP-TCF). The FP-TCF acceptor was synthesized through two consecutive multiple steps, one-pot reactions to achieve a good overall yield of 50%, which is higher than that of making CF3-TCF. The reduced π–π stacking and fine-tuned bond-length alternation boost the nonlinear optical activities of FP-TCF-based heptamethines in plasmon-coupled EO polymer waveguides, leading to larger EO coefficients (up to 205%) over those of the TCF-based chromophores. More importantly, we demonstrate for the first time an ultralarge molecular first hyperpolarizability of 8437 × 10–30 esu at 1304 nm for M1a-FP-ON, which exceeds the results of two best-performing but synthetically demanding push–pull tetraene chromophores. The results mark an important milestone in developing highly efficient push–pull polymethines with good stability and synthetic scalability for photonic applications.

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Section: ■ Results and Discussionmentioning

confidence: 95%

Section: Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Efficient, Stable, and Scalable Push–Pull Heptamethines for Electro-Optics

Zhang

Zou

et al. 2022

Chem. Mater.

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“…The dotted curve represents the glass temperature at R = 16 nm for the case of pure HC.polarization-dependent SP extinction bands from each irradiated area ͑representing a single time delay ⌬t͒ are recorded by conventional transmission spectroscopy ͑Shimadzu 3100 UV/VIS/NIR spectrometer͒. These bands are then analyzed by the method of moments 29. …”

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confidence: 99%

Time-resolved investigation of laser-induced shape transformation of silver nanoparticles

et al. 2009

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Laser-induced permanent shape transformation dynamics of glass-embedded silver nanoparticles is investigated by a pulse-pair irradiation technique, where the nanoparticles are irradiated by pairs of time-delayed femtosecond laser pulses. The temporal evolution of surface plasmon extinction bands is obtained up to a time delay of 1 ns. We find that the aspect ratio of the modified nanoparticles, i.e., the observed dichroism, reduces rapidly to a minimum level within 20 ps after the laser irradiation. From that interpulse delay onward, the resulting aspect ratio stays at that minimum level until 100 ps. Subsequently, for longer time delays, the aspect ratio increases again until 1 ns. Temperature modeling of the nanoparticle-glass system gives evidence that the intermediately reduced dichroism is due to the high diffusion mobility that emitted silver ions can possess within a shell of heated glass around the nanoparticle, in a time window of 100 ps. For longer time delays the size of the heated glass shell gets reduced, thereby limiting the range of ionic diffusion. The theoretical estimations confirm the experimental results and suggest that the nanoparticle shape changes depend strongly on the thermal situation induced to the surrounding glass.

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“…22 Then the polarization-dependent extinction bands from each irradiated area ͑representing one time delay ⌬t͒ are recorded by conventional transmission spectroscopy. These bands are then analyzed by the method of moments, 26 which is a statistical method allowing an objective comparison of the spectral parameters of extinction bands. The first moment defines the central position of a band; the second moment represents its bandwidth.…”

Section: Methodsmentioning

confidence: 99%

Ultrafast dynamics of silver nanoparticle shape transformation studied by femtosecond pulse-pair irradiation

et al. 2009

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Spherical silver nanoparticles embedded in glass were irradiated by pairs of time-delayed laser pulses with equal intensities resulting in delay-dependent nanoparticle shape transformations. The corresponding persistent changes in the surface-plasmon extinction bands are analyzed as a function of time delay and relative polarization of the pulse pairs. We find that the strongest nanoparticle shape changes, i.e., the highest aspect ratios, are achieved when the delay between pulse pairs is less than 3 ps. After 10 ps the dichroism is strongly reduced in the case of pulse pairs having identical polarization and vanishes using pulse pairs with orthogonal polarization. Using an extended two-temperature model, the time dependence of directed and isotropic thermal electron emissions was estimated to decay on a time scale of a few picoseconds. Our results strongly suggest that the electron and following ion emission from the nanoparticles are finished within less than 20 ps, and the directional memory is favorably defined by directed emission of hot electrons interacting with the laser field.

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Application of the method of moments to the study of the electronic spectra of organic dyes

Cited by 13 publications

References 1 publication

Efficient, Stable, and Scalable Push–Pull Heptamethines for Electro-Optics

Efficient, Stable, and Scalable Push–Pull Heptamethines for Electro-Optics

Time-resolved investigation of laser-induced shape transformation of silver nanoparticles

Ultrafast dynamics of silver nanoparticle shape transformation studied by femtosecond pulse-pair irradiation

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