Showing papers on "Hyperpolarizability published in 2014"
TL;DR: A large variety of common methods for computing the properties of modern high-performance chromophores were surveyed and compared these results with prior experimental hyper-Rayleigh scattering (HRS) and absorbance data, suggesting composite methods could greatly improve the accuracy of calculations of β and λmax.
Abstract: ConspectusOrganic glasses containing chromophores with large first hyperpolarizabilities (β) are promising for compact, high-bandwidth, and energy-efficient electro-optic devices. Systematic optimization of device performance requires development of materials with high acentric order and enhanced hyperpolarizability at operating wavelengths. One essential component of the design process is the accurate calculation of optical transition frequencies and hyperpolarizability. These properties can be computed with a wide range of electronic structure methods implemented within commercial and open-source software packages. A wide variety of methods, especially hybrid density-functional theory (DFT) variants have been used for this purpose. However, in order to provide predictions useful to chromophore designers, a method must be able to consistently predict the relative ordering of standard and novel materials. Moreover, it is important to distinguish between the resonant and nonresonant contribution to the hyp...
162 citations
TL;DR: In this paper, the molecular structure of 1-azanapthalene-8-ol was calculated by the B3LYP density functional model with 6-31G(d,p) basis set by Gaussian program.
Abstract: The molecular structure of 1-azanapthalene-8-ol was calculated by the B3LYP density functional model with 6-31G(d,p) basis set by Gaussian program. The results from natural bond orbital analysis have been analyzed in terms of the hybridization of atoms and the electronic structure of the title molecule. The stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital analysis. The electron density based local reactivity descriptors such as the Fukui functions were calculated. The dipole moment (μ) and polarizability (α), anisotropy polarizability (∆α) and rst order hyperpolarizability (βtot) of the molecule have been reported.
120 citations
TL;DR: The two-photon emission spectra and the first hyperpolarizabilities of these particles were obtained using, in particular, a hyper-Rayleigh scattering technique, outlining the quantum cluster regime.
Abstract: By developing a new method for synthesizing atomically monodisperse Au15 nanoclusters stabilized with glutathione molecules and using the current state-of-the-art methods for synthesizing monodisperse protected Au25 nanoclusters, we investigated their nonlinear optical (NLO) properties after two-photon absorption. The two-photon emission spectra and the first hyperpolarizabilities of these particles were obtained using, in particular, a hyper-Rayleigh scattering technique. The influence on NLO of the excitation wavelength, the size as well as the nature of the ligands is also explored and discussed. Au15, the smallest stable thiolated gold nanocluster, presents remarkable nonlinear properties with respect to two-photon processes. The two-photon absorption cross-section at 780 nm for Au15 is ∼65 700 GM. This experimental cross-section value points to a quantum yield for two-photon emission of about 3 × 10−7 at 475 nm for Au15. The first hyperpolarizability β for Au15 clusters (509 × 10−30 esu), as compared to Au25 clusters (128 × 10−30 esu), is larger considering the difference in the number of gold atoms. Also, 1030 β per atom values reported for Au15 and Au25 clusters are more than two orders of magnitude larger than the values reported for Au NPs in the size range 10–50 nm, outlining the quantum cluster regime.
108 citations
TL;DR: The linear polarizability and the first order hyperpolarizability values of the investigated molecule have been computed using HF/DFT/6-31G(d,p) methods on the finite field approach.
99 citations
TL;DR: This study evaluates the utility of the long-range corrected (LC) DFT methods for computation of the molecular second-order nonlinear optical response and examines systematic tuning of the range-separation parameter to enforce Koopmans'/ionization potential theorem.
Abstract: Organic electro-optic (OEO) materials integrated into silicon–organic hybrid devices afford significant improvements in size, weight, power, and bandwidth performance of integrated electronic/photonic systems critical for current and next generation telecommunication, computer, sensor, transportation, and defense technologies. Improvement in molecular first hyperpolarizability (β), and in turn electro-optic activity, is crucial to optimizing device performance. Common hybrid density functional theory (DFT) methods, while attractive due to their computational scaling, often perform poorly for optical properties in systems with substantial intramolecular charge-transfer character, such as OEO chromophores. This study evaluates the utility of the long-range corrected (LC) DFT methods for computation of the molecular second-order nonlinear optical response. We compare calculated results for a 14-molecule benchmark set of OEO chromophores with the corresponding experimentally measured β and one-photon absorpti...
99 citations
TL;DR: Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis and the results confirm the occurrence of intramolecular charge-transfer (ICT) within the molecule.
75 citations
TL;DR: A set of linear and dissymmetric BODIPY-bridged push-pull dyes are synthesized and the electron-donating substituents are anisole and dialkylanilino groups, which show diverse photochemistry and electrochemistry, with several reversible reduction waves for the tetracyanobutadiene moiety.
Abstract: A set of linear and dissymmetric BODIPY-bridged push-pull dyes are synthesized. The electron-donating substituents are anisole and dialkylanilino groups. The strongly electron-accepting moiety, a 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) group, is obtained by insertion of an electron-rich ethyne into tetracyanoethylene. A nonlinear push-pull system is developed with a donor at the 5-position of the BODIPY core and the acceptor at the 2-position. All dyes are fully characterized and their electrochemical, linear and nonlinear optical properties are discussed. The linear optical properties of dialkylamino compounds show strong solvatochromic behavior and undergo drastic changes upon protonation. The strong push-pull systems are non-fluorescent and the TCBD-BODIPY dyes show diverse photochemistry and electrochemistry, with several reversible reduction waves for the tetracyanobutadiene moiety. The hyperpolarizability μβ of selected compounds is evaluated using the electric-field-induced second-harmonic generation technique. Two of the TCBD-BODIPY dyes show particularly high μβ (1.907 μm) values of 2050 × 10(-48) and 5900 × 10(-48) esu. In addition, one of these dyes shows a high NLO contrast upon protonation-deprotonation of the donor residue.
70 citations
TL;DR: The use of physically-adjusted range-separated parameter (μ) together with long-range corrected exchange-correlation functionals is shown not to be reliable for calculating the polarizability and the second hyperpolarizability of large π-conjugated systems.
Abstract: The use of physically-adjusted range-separated parameter (μ) together with long-range corrected exchange–correlation functionals is shown not to be reliable for calculating the polarizability (α) and the second hyperpolarizability (γ) of large π-conjugated systems. This statement has been substantiated by calculating the polarizability and the second hyperpolarizability of increasingly large polydiacetylene and polybutatriene chains in comparison with reference data evaluated at the coupled-cluster singles and doubles with perturbative estimation of the triples [CCSD(T)] level. Further comparisons highlight that long-range corrected exchange–correlation functionals with conventional and larger range-separated parameters perform better for α (μ = 0.47) and γ (μ = 0.33 and 0.47) but for polybutatriene chains none can describe satisfactorily the chain length evolution of γ. On the other hand, Moller–Plesset second- and fourth-order values are in closer agreement with CCSD(T), except for γ of polybutatriene, which is strongly overestimated.
70 citations
TL;DR: In this article, the density functional theory (DFT) was used to calculate the HOMO-LUMO energy gaps and first-order hyperpolarizability (β) of new Y-type chromophores.
Abstract: New Y-type chromophores FTC-yh1 and FTC-yh2 containing bis(N,N-diethyl)aniline as a novel electron-donor, thiophene as a π-conjugated bridge and tricyanofuran (TCF) as an acceptor have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These chromophores showed better thermal stability with their decomposition temperatures all above 240 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped film-A containing 25 wt% chromophore FTC-yh1 displayed a value of 149 pm V−1 at 1310 nm, and the doped film-B containing FTC-yh2 showed a value of 143 pm V−1 at the concentration of 25 wt%. These values are almost four times higher than the EO activity of usually reported traditional single (N,N-diethyl)aniline nonlinear optical (NLO) chromophores FTC. High r33 values indicated that the double donors of the bis(N,N-diethyl)aniline unit can efficiently improve the electron-donating ability and reduce intermolecular electrostatic interactions, thus enhancing the macroscopic EO activity. These properties, together with the good solubility, suggest the potential use of the new chromophores as advanced material devices.
66 citations
TL;DR: The linear polarizability and first order hyperpolarizability of the studied molecule indicate that the compound is a good candidate of nonlinear optical materials.
65 citations
TL;DR: In this article, the pyrrole moiety bridge has been modified with the electron withdrawing group (−Br, −NO2) substituted benzene ring, and side phenyl groups to chromophores A and B can increase the thermal and chemical stability and reduce dipole-dipole interactions.
Abstract: Three novel second order nonlinear optical chromophores based on julolidinyl donors and tricyanovinyldihydrofuran (TCF) acceptors linked together via modified pyrrole π-conjugation (chromophores A and B) or thiophene moieties (chromophore C) as the bridges have been synthesized and systematically characterized. In particular, the pyrrole moiety bridge has been modified with the electron withdrawing group (–Br, –NO2) substituted benzene ring. The introduction of side phenyl groups to chromophores A and B can increase the thermal and chemical stability and reduce dipole–dipole interactions so as to translate their hyperpolarizability (β) values into bulk EO performance more effectively than chromophore C. Moreover, DFT calculations suggested that the additional electron withdrawing groups in chromophores A and B could increase the β value compared to that of chromophore D without substituted phenyl groups, and they showed different influences on the solvatochromic behavior, thermal stability, and electro-optic activity of the chromophores. EO responses (r33 values) of guest–host polymers containing pyrrole-bridged chromophores were reported. Incorporation of chromophores A and B into APC provided large electro-optic coefficients of 86 and 128 pm V−1 at 1310 nm with a high loading of 30 wt%. Film-C/APC containing 25 wt% of chromophore C provides an EO coefficient of 98 pm V−1.
TL;DR: The predicted first hyperpolarizability shows that the 4N4MSP molecule has a reasonably good nonlinear optical (NLO) behavior.
TL;DR: In this paper, the nonlinear optical behavior of 2(3),9(10),16(17),23(24)-tetrakis-(4-aminophenoxy)phthalocyaninato indium(III) chloride (2) and its carbon nanotube composite in dimethylsulfoxide (DMSO) and dimethylformamide (DMF) solutions is described.
Abstract: The nonlinear optical behavior of 2(3),9(10),16(17),23(24)-tetrakis-(4-aminophenoxy)phthalocyaninato indium(III) chloride (2) and its carbon nanotube composite in dimethylsulfoxide (DMSO) and dimethylformamide (DMF) solutions is described. The nonlinear third-order susceptibility and second-order hyperpolarizability values are also reported. A large nonlinear absorption that increased on covalent linking with single-walled carbon nanotubes (SWCNTs) was observed for the compound in DMSO. The nanosecond nonlinear absorption and the optical limiting behavior of this complex are shown to be dominated by a strong excited state absorption from a two-photon pumped state. The optical limiter using the new nanocomposite material (SWCNT-2) in the appropriate solvent showed a much lower threshold for optical limiting together with a much lower transmission at high fluences than previously reported nanocomposite limiters. The optical properties of the phthalocyanine and its conjugate were found to show high sensitivi...
TL;DR: In this article, the structural, electronic and nonlinear optical properties of the two important fullerene-like cages of B 12 N 12 and Al 12 n 12 nanostructures with the groups III, IV and V dopants are investigated through density functional theory (DFT) calculations.
TL;DR: In this paper, the authors reported a quantum chemical calculation on three complexes (Ad-Li, Ad-Na, and Ad-K) which were obtained by substituting the H atom of methine position in Ad with alkali metal (Li, Na, and K).
Abstract: Adamantane (Ad) is the parent molecule of diamondoids, which has been the subject of much chemical interest because of its highly symmetric cage structure. Many valuable papers demonstrated that the H atom of the methine position in Ad is highly reactive. Compared with highly symmetric carbon structures such as graphene and single-walled carbon nanotubes (SWCNTs), Ad only possesses σ bonds. In this work, we report a quantum chemical calculation on three complexes (Ad-Li, Ad-Na, and Ad-K), which were obtained by substituting the H atom of methine position in Ad with alkali metal (Li, Na, and K). Interestingly, the substitution by alkali metals leads to absorption within the visible region. The maximum absorption wavelengths of the complexes show a red shift trend from the Li to the K complex. This trend indicates that the crucial transition energy becomes smaller, which might lead to a larger nonlinear optical response. Among the three structures, the largest first static hyperpolarizability (βtot) of the ...
TL;DR: Harmonic frequencies, molecular structure, NBO and HOMO, LUMO analysis and detonation properties of (S)-2-(2-oxopyrrolidin-1-yl) butanamide, and thermodynamic properties of title compound at different temperatures have been calculated.
TL;DR: In this article, the molecular structure and spectroscopic properties of (E)-2-([3,4-dimethylphenyl)imino]methyl)-3-methoxyphenol were investigated by X-ray diffraction, FT-IR and UV-vis spectroscopy.
TL;DR: In this work, vibrational spectral analysis on the solid state of 2,5-dichlorophenylisocyanate have been investigated both the experimental and theoretical vibrational data indicate the presence of various functional groups within the title of molecule.
TL;DR: The vibrational spectral analysis was carried out using FT-IR and FT-Raman spectroscopy for 2,4-bis(2-methoxyphenyl)-1-phenylanthracene-9,10-dione and the stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis.
TL;DR: The stability of the molecule arising from hyper conjugative interaction and charge delocalization has been analyzed using NBO analysis, and the thermodynamic properties of the compound were calculated at different temperatures and corresponding relations between the properties and temperature were studied.
TL;DR: In this paper, the 8-hydroxyquinolinium 3,5-dinitrobenzoate crystals were grown using slow evaporation solution technique and the structure was confirmed by single crystal X-ray diffraction and nuclear magnetic resonance analyses.
TL;DR: The results demonstrate the key role of intermolecular π-π stacking interactions and charge in open-shell (supra)molescular systems to achieve enhanced third-order NLO properties.
Abstract: The impact of intermolecular interactions on the third-order nonlinear optical (NLO) properties of open-shell molecular aggregates has been elucidated by considering one-dimensional aggregates of π–π stacked phenalenyl radicals with different intermolecular distances and the long-range corrected spin-unrestricted density functional theory method. In the phenalenyl dimer, which can be considered as a diradicaloid system, the diradical character strongly depends on the intermolecular distance, and the larger the intermolecular distance is, the larger the diradical character becomes. Then, around the equilibrium stacking distance that corresponds to an intermediate diradical character, its second hyperpolarizability (γ) is maximized and its value per monomer exhibits about a 30-fold enhancement with respect to the isolated phenalenyl monomer. This suggests that equilibrium is an optimal compromise between localization and delocalization of the radical electron pairs in such pancake bonding. No such effect was observed for the closed-shell coronene dimer. Moreover, when going from the dimer (diradical) to the tetramer (tetraradical), the γ-enhancement ratio increases nonlinearly with the aggregate size, whereas switching from the singlet to the highest spin (quintet) state causes a significant reduction of γ. Finally, for the tetramer, another one-order enhancement of γ is achieved for the dicationic singlet relative to its singlet neutral state. These results demonstrate the key role of intermolecular π–π stacking interactions and charge in open-shell (supra)molecular systems to achieve enhanced third-order NLO properties.
TL;DR: In this article, the authors presented the synthesis of three chromophores containing different conjugated electron-bridges by acidic and alkaline formylation, which played the different roles of electron-bridge, site-isolator and electron- isolator, generating intriguing property variations of electron distribution of push-pull structure.
Abstract: In electro-optic (EO) materials, realization of large EO coefficients for organic EO materials requires the simultaneous optimization of chromophore first hyperpolarizability, acentric order, molecular shape etc. As these parameters are complicatedly inter-related, thorough analyses are required to understand the dependence of macroscopic EO activity upon chromophore structure and property. Herein, we presented the synthesis of three chromophores containing different conjugated electron-bridges by acidic and alkaline formylation. Electron-rich moieties thiophene and formyl-thiophene in the different positions of chromophores played the different roles of electron-bridge, site-isolator and electron-isolator, generating intriguing property variations of electron distribution of push–pull structure, intramolecular charge-transfer, solvatochromism, microscopic hyperpolarizability and related density functional theory calculation results. In addition these molecular structure–property relationships were rationally related to the EO activities to understand the impact of microscopic molecular property on macroscopic EO activities of materials.
TL;DR: In this article, a Stone-Wales defect ring is constructed at one end of the ZCNTs, forming a novel nanostructure [5.7]3ZCNT, which has a closed-shell ground state with a large dipole moment, polarizability, and first hyperpolarizability.
Abstract: Based on (6, 0) zigzag carbon nanotubes (ZCNTs), a Stone–Wales defect ring ([5.7]3) is constructed at one end of the ZCNTs, forming a novel nanostructure [5.7]3ZCNT. The introduction of [5.7]3 breaks the centrosymmetry of the nanotube and remarkably changes electronic and magnetic properties of the nanotube. Unlike the (6, 0)ZCNT which has an open-shell singlet ground state, the [5.7]3ZCNT has a closed-shell singlet ground state with a large dipole moment, polarizability, and first hyperpolarizability. Interestingly, the [5.7]3ZCNT itself has a donor–π–acceptor framework, in which the Stone–Wales defect ring serves as an electron donor (D) while the zigzag nanotube works as an electron acceptor (A) and a conjugated bridge (π). Moreover, increasing both the tube diameter and tube length could enhance second-order nonlinear optical (NLO) responses, with the former being more effective than the latter.
TL;DR: The unexpectedly high quadratic hyperpolarizability values of simple Ru and Pt alkynyl complexes have been measured by the EFISH technique, and this prompted us to investigate their potential as molecular building blocks for composite films with second harmonic generation properties.
TL;DR: The optimization of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed and the calculated first hyperpolarizability is high and the title compound is an attractive candidate for further studies in nonlinear optical applications.
TL;DR: The study shows that various properties of sumanene could be finely tuned for the application in the areas closely related to the materials science, including organic electronics and materials science engineering.
Abstract: We investigated the effects of substitution on the sumanene benzylic CH2 groups with BH and NH groups using density functional theory computations. Our study shows that various properties of sumanene could be finely tuned for the application in the areas closely related to the materials science. Structural properties are significantly altered with such modifications and other properties as well. Charge distributions were evaluated through natural population analysis (NPA), while stability of investigated structures was investigated using quantum molecular descriptors. Using molecular orbital analysis further insight into the effects of substitution was obtained. Potential of sumanene as a candidate for application in the field of organic electronics is assessed through calculations of exciton binding energy. Non-linear optical properties of investigated structures were investigated using the first hyperpolarizability tensor. Special attention was paid to the aromaticity of sumanene. This property was evaluated employing NICS parameter while for detailed study of obtained results we used NBO and NBOdel analysis.
TL;DR: The presence anthracene ring modes in the SERS spectrum suggest a tilted orientation with respect to the metal surface, and the methyl groups in the title molecule are also close to theMetal surface.
TL;DR: Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction and the HOMO-LUMO energy gap explains the charge interaction taking place within the molecule.
TL;DR: In this article, three new supramolecular compounds [H2TPP]1.5, H2TPP2.5 and H2P3.5 composed of vanadium substituted Keggin-type polyoxometalate (POM) anion [SW12−nVnO40](2+n)− (n = 0−2) were prepared and characterized.
Abstract: Three new supramolecular compounds [H2TPP]1.5[SW11VO40]·5CH3CN·4H2O 1, [H2TPP]2[SW10V2O40]·4CH3CN·3H2O 2, and [H2TPP][SW12O40]·4H2O 3 composed of [H2TPP]2+ cation and vanadium substituted Keggin-type polyoxometalate (POM) anion [SW12−nVnO40](2+n)− (n = 0–2) were prepared and characterized. The third-order nonlinear optical (NLO) and optical limiting (OL) properties of resulting hybrids were studied by using an Nd:YAG laser at 532 nm with a pulse duration of τ = 7 ns. The results demonstrate that all of these supramolecular compounds have significant nonlinear reverse saturated absorption, self-defocusing behavior, and good OL performance, especially for compound 1, which has a second hyperpolarizability γ value of 7.05 × 10−29 (esu) and exhibits a comparable OL performance with the most well-known OL materials such as In(Pc*)Cl indicating that they are potentially excellent NLO materials. Remarkably, it was also observed that the degree of vanadium substitution in POM anions corresponding to different onset of reduction potential influences the NLO and OL properties of the resulting compounds: third-order NLO and OL properties of compound 2 are inferior to those of compound 1, and are better than those of compound 3. Both their second hyperpolarizability γ values and the OL performance were observed to be inversely proportional to the HOMO–LUMO gaps of the resulting compounds. The excited charge transfer from porphyrin to POM anions in the supramolecular compounds when exposed to laser irradiation is thought to play key role in the enhancement of NLO and OL response.