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The Breit interaction (transverse interaction in the low-frequency limit) [[26]] can be expressed as, HT ht Graph (4)and the leading QED effects (vacuum polarization and self-energy) have been included in subsequent configuration interaction calculations, where optimization is on a weighted sum of energies. [Extracted from the article]

The oxyfluoride phosphate glass doped with europium oxide was synthesized by melt quenching technique. The structural and spectroscopic analysis has been carried out by Raman, absorption, photoluminescence, phonon side band and lifetime analysis. The absorption spectrum revealed the characteristic transitions between the 7F0 ground state and 7F1 first excited state to the upper-lying electronic states. The several J-O parameters: oscillator strength, radiative transition probability, stimulated emission cross-section and branching ratio. The local structure around the Eu3+ ions and the phonon energy of oxyfluoride phosphate glass have been confirmed on the basis of PSB associated with the 7F0→5D2 transition. The highest excitation spectrum showed at 395 nm for transition 7F0→5L6. The emission spectrum showed two major peaks corresponding to 591 nm orang emission (5D0→7F1) and 613 nm red emission (5D0→7F2). This work confirmed that 1 mol% Eu2O3 doped oxyfluoride phosphate glass performs a high potential for using as efficient luminescence materials for solid-state lighting application, especially for reddish-orange light-emitting glass. [ABSTRACT FROM AUTHOR]

The absorption spectra of a series of dithiocarboxylates were investigated in the ultraviolet–visible region. Two questions that this study aimed to address were as follows: (1) What transitions give rise to the features in the electronic spectra? And (2) what are the long- and short-range substituent effects on the absorption spectra? A series of 11 dithiocarboxylates were prepared as organic soluble salts. Time-dependent density functional theory (TDDFT) was used to calculate excited state energies and oscillator strengths of electronic transitions. TDDFT at the CAM-B3LYP/def2-TZVPD level of theory predicts two low-energy n → π* transitions and two π → π* transitions at higher energy, consistent with the experimental spectra. This state ordering and density is in contrast to the better studied thiocarbonyls for which only two transitions within the singlet manifold appear in the UV–visible region. For derivatives of dithiobenzoate, the energy of the three lowest energy states are insensitive to changes to substituents para to the dithiocarboxylate group. In contrast, the energy of the highest ππ* state varies by 0.78 eV. This work shows that the results of TDDFT calculations can be used to predict the electronic absorption spectra of dithiocarboxylates, providing a useful tool for designing dithiocarboxylate light absorbers. [ABSTRACT FROM AUTHOR]

Fluorophores play crucial roles in chemical and biological imaging. An efficient computational model that evaluates the electronic properties of molecules accurately would be a useful tool for discovering novel fluorophores. Tree‐based ensemble and graph neural network (GNN) methods have been regarded as attractive models for predicting molecular properties. Here, we present a benchmark test using three tree‐based ensemble methods (Random Forest, LightGBM, and XGBoost) and three GNNs (directed message passing neural network [D‐MPNN], attention message passing neural network [AMPNN], and DimeNet++) for predicting electronic transition properties such as excitation energies and oscillator strengths. From our benchmark, DimeNet++ was identified as the most accurate model to predict electronic transition properties. The average root mean square error of DimeNet++ for predicting the HOMO–LUMO gap was 0.11 eV whereas those of the other methods exceeded 0.3 eV. D‐MPNN predicted fastest without sacrificing accuracy. Our results show that DimeNet++ and D‐MPNN may serve as helpful evaluators for novel fluorophore design when combined with molecular generation methods. [ABSTRACT FROM AUTHOR]

The detection of gravitational waves and electromagnetic signals from the neutron star merger GW170817 has provided evidence that these astrophysical events are sites where the r-process nucleosynthesis operates. The electromagnetic signal, commonly known as kilonova, is powered by the radioactive decay of freshly synthesized nuclei. However, its luminosity, colour and spectra depend on the atomic opacities of the produced elements. In particular, opacities of lanthanides and actinides elements, due to their large density of bound–bound transitions, are fundamental. The current work focuses on atomic structure calculations for lanthanide and actinide ions, which are important in kilonovae modelling of ejecta spectra. Calculations for Nd III and U III, two representative rare-earth ions, were achieved. Our aim is to provide valuable insights for future opacity calculations for all heavy elements. We noticed that the opacity of U III is about an order of magnitude greater than the opacity of Nd III due to a higher density of levels in the case of the actinide. [ABSTRACT FROM AUTHOR]

In the optically thin regime, the intensity ratio of the two Si iv resonance lines (1394 and 1403 Å) are theoretically the same as the ratio of their oscillator strengths, which is exactly 2. Here, we study the ratio of the integrated intensity of the Si iv lines (R = ∫I1394(λ)dλ/∫I1403(λ)dλ) and the ratio of intensity at each wavelength point (r(Δλ) = I1394(Δλ)/I1403(Δλ)) in two solar flares observed by the Interface Region Imaging Spectrograph. We find that at flare ribbons, the ratio R ranges from 1.8 to 2.3 and would generally decrease when the ribbons sweep across the slit position. In addition, the distribution of r(Δλ) shows a descending trend from the blue wing to the red wing. In loop cases, the Si iv line presents a wide profile with a central reversal. The ratio R deviates little from 2, but the ratio r(Δλ) can vary from 1.3 near the line center to greater than 2 in the line wings. Hence we conclude that in flare conditions, the ratio r(Δλ) varies across the line, due to the variation of the opacity at the line center and line wings. We notice that, although the ratio r(Δλ) could present a value that deviates from 2 as a result of the opacity effect near the line center, the ratio R is still close to 2. Therefore, caution should be taken when using the ratio of the integrated intensity of the Si iv lines to diagnose the opacity effect. [ABSTRACT FROM AUTHOR]

The dipole transition‐matrix elements (DTMEs) and oscillator strengths (OSs) for the doubly excited states (DESs) in heliumlike carbon are investigated using the correlated exponential wavefunctions (CEW). The interactions between the charged particles are taken care of by using both Coulomb and screened Coulomb (Debye–Hückel) potentials. The singly excited 1s3p 1P state and doubly excited 2p2 1De state are also calculated using CEW. The singly excited states of C4+ in terms of Debye length (DL) are calculated using the Ritz variational principle. The DESs for different DLs are determined using the stabilization method. The DTMEs and OSs for the transitions between the 2p2 1De state and the 1s2p 1P, 1s3p 1P, 2s2p+1Po, 2s3p−1Po, 2s3p+1Po, 2p3d 1Po states, along with the 2p2 1De resonance parameters are reported for various DLs. The benchmark data for DTMEs and OSs for the DESs in the C4+ ion in pure Coulomb and screened Coulomb environments, obtained by employing highly CEW functions and utilizing the stabilization method, are reported for the first time. [ABSTRACT FROM AUTHOR]

The emergence of many fascinating dynamic behaviors is affected by more than one interaction among the elements or cells in a network. In fact, the concurrence and competition of different types of effects among subsystems show a strong connection to the dynamic transition process between oscillation patterns. Here, a network of generic oscillators with mixed attractive-repulsive couplings is introduced to demonstrate the transition from oscillatory states to stationary equilibria, specifically for van der Pol oscillators and Lorenz oscillators. Through the observation of the normalized amplitude changing with the coupling strength, the sudden and irreversible transition appears in both systems, which has a close relation to the mutual repulsion on coupled oscillators. Whereas, for coupled van der Pol oscillators, three typical transition scenarios are found by varying the weight ratio of these two couplings, while the Lorenz system shows only one transition mode no matter how the weight ratio changes. Besides, in the cases of explosive transitions, the coexistence areas of oscillatory and death states also reveal a distinct manifestation for periodic and chaotic systems. The details of theoretical critical transition points on the first-order phase transition are also obtained. Our results pave a new way to control the explosive phenomenon, which is crucial to explain the sudden oscillation quenching and the coexistence of oscillatory and stationary states in biological as well as chemical systems. [ABSTRACT FROM AUTHOR]

To increase the emission intensity of Pr SP 3+ sp ions, Yb SP 3+ sp ions appear as an efficient sensitizer [[13]]. Due to a non-exponential character of the decay data, we have determined the experimental lifetime as being equal to the effective lifetime defined as HT ht Graph (4) Graph: Fig. [[36]]) HT ht Graph (5)where I i SB Pr-Yb sb and I i SB Pr sb are the effective lifetimes with and without Yb SP 3+ sp -coping, respectively, but for the same concentration of Pr SP 3+ sp ions. Emission spectra Emission spectra of Ln-doped samples TPr and TPrYb were measured in the same conditions allowing one to compare their relative intensities; additionally, in order to demonstrate the effect of the Pr SP 3+ sp ion concentration ( I N i SB Pr sb ; see Table 1) on the emission spectra, the PL signal of both samples (in arbitrary units) has been divided by I N i SB Pr sb . [Extracted from the article]

In the present work, we have reported the energy levels, wavelengths, weighted oscillator strengths, and transition probabilities for electric dipole (E1) transitions of magnesium like platinum (Pt LXVII, Z=78). Accurate knowledge of Mg-like ions are of great importance for astrophysics, plasma, and thermonuclear fusion research. The atomic data are calculated with the AUTOSTRUCTURE code, where relativistic corrections are introduced according to the Breit–Pauli distorted wave approach. In the calculations, quantum electrodynamics effects and correlation contributions have been considered. The present results are in good agreement with other available values. There are no experimental works for Pt LXVII in the literature. We predict new theoretical data for several levels will be helpful for future experimental works. [ABSTRACT FROM AUTHOR]

This study investigates the terahertz performance of a voltage tunable AlGaAs/GaAs asymmetric step-like coupled double quantum well infrared photodetector structure based on intersubband transitions. The left part of the barrier is n-type doped to eliminate the interaction of the impurities with an electron in the quantum well. The coupled double quantum wells in the structure enable the adjustment of the dipole moment and the oscillator strength for the intersubband transition resonance absorption, providing wavelength tunable and selectable performance. When the applied voltage is increased, the photoresponse spectra dominated by a transition from the ground subband level to the second subband level with an energy of 17 meV (∼ 4.1 THz) shifts to the transition from the ground subband level to the first subband level with an energy of 10.2 meV (∼ 2.5 THz). [ABSTRACT FROM AUTHOR]

Computational screening is highly fruitful for initial studies of unknown molecules due to the capability of this tool in molecular discovery and the continuous improvement of computational methods. This article reports how computational studies on more than 300 organic molecules can identify thermally activated delayed fluorescent (TADF) emitters that emit light within the range of red up to near‐infrared (NIR) with high TADF rates. According to time‐dependent density functional theory (TD‐DFT) computations, the best compounds exhibit a low singlet‐triplet energy gap of 0.03 eV and oscillator strength of 0.0425, leading to a high rate of delayed fluorescence decay of 1.4483 μs−1. Additionally, an experimental‐theory calibration approach is used as an adjunct to experimental research in the future, and emission wavelengths in promising charge‐transfer compounds are estimated as large as 689 nm. [ABSTRACT FROM AUTHOR]

Dy3+-doped lithium barium bismuth phosphate glasses were synthesized by the melt-quenching. The structural characteristics of the synthesized glasses were investigated by Fourier transform infrared (FTIR) spectroscopy. Symmetric and asymmetric vibrations of phosphorous oxygen groups were prominent bands in the FTIR spectra. Judd–Ofelt theory have been evaluated by the intensities of absorption bands in order to calculate oscillator strength (f). Luminescence intensity increases with increase in BaO content due to substitution of Ba2+ replacing Bi3+ which lead more void spaces providing enough space for Dy3+ ions to fit in. The branching ratio β parameter was distinguished to be maximum for the emission transition of 4F9/2 → 6H13/2 with the values of 0.59. LBBPDy glasses reveal an ideal warm white region when observed in CIE diagram. Our investigation reveals that the synthesized glasses may be utilized as a solid-state lighting material in various technological and industrial applications. [ABSTRACT FROM AUTHOR]

Raman scattering and ab initio Raman/phonon calculations, supported by X-ray diffraction, are combined to study the vibrational properties of Zn1−xBexTe under pressure. The dependence of the Be–Te (distinct) and Zn–Te (compact) Raman doublets that distinguish between Be- and Zn-like environments is examined within the percolation model with special attention to x ~ (0,1). The Be-like environment hardens faster than the Zn-like one under pressure, resulting in the two sub-modes per doublet getting closer and mechanically coupled. When a bond is so dominant that it forms a matrix-like continuum, its two submodes freely couple on crossing at the resonance, with an effective transfer of oscillator strength. Post resonance the two submodes stabilize into an inverted doublet shifted in block under pressure. When a bond achieves lower content and merely self-connects via (finite/infinite) treelike chains, the coupling is undermined by overdamping of the in-chain stretching until a «phonon exceptional point» is reached at the resonance. Only the out-of-chain vibrations «survive» the resonance, the in-chain ones are «killed». This picture is not bond-related, and hence presumably generic to mixed crystals of the closing-type under pressure (dominant over the opening-type), indicating a key role of the mesostructure in the pressure dependence of phonons in mixed crystals. [ABSTRACT FROM AUTHOR]

Higher plants defend themselves from bursts of intense light via the mechanism of Non-Photochemical Quenching (NPQ). It involves the Photosystem II (PSII) antenna protein (LHCII) adopting a conformation that favors excitation quenching. In recent years several structural models have suggested that quenching proceeds via energy transfer to the optically forbidden and short-lived S 1 states of a carotenoid. It was proposed that this pathway was controlled by subtle changes in the relative orientation of a small number of pigments. However, quantum chemical calculations of S 1 properties are not trivial and therefore its energy, oscillator strength and lifetime are treated as rather loose parameters. Moreover, the models were based either on a single LHCII crystal structure or Molecular Dynamics (MD) trajectories about a single minimum. Here we try and address these limitations by parameterizing the vibronic structure and relaxation dynamics of lutein in terms of observable quantities, namely its linear absorption (LA), transient absorption (TA) and two-photon excitation (TPE) spectra. We also analyze a number of minima taken from an exhaustive meta-dynamical search of the LHCII free energy surface. We show that trivial, Coulomb-mediated energy transfer to S 1 is an unlikely quenching mechanism, with pigment movements insufficiently pronounced to switch the system between quenched and unquenched states. Modulation of S 1 energy level as a quenching switch is similarly unlikely. Moreover, the quenching predicted by previous models is possibly an artifact of quantum chemical over-estimation of S 1 oscillator strength and the real mechanism likely involves short-range interaction and/or non-trivial inter-molecular states. [ABSTRACT FROM AUTHOR]

We report a theoretical study of electronic excitation in CH3Cl and CF3Cl by electron impact. Momentum-transfer-dependent generalized oscillator strengths (GOSs) are calculated for transitions to low-lying excited singlet-states at the equation-of-motion coupled-cluster singles and doubles level. The influence of molecular vibration is taken into account in the calculation. The theoretical results show reasonable overall agreement with experimental data reported in the literature. The shapes of the GOS profiles reveal that the 1 1E state of CH3Cl has a valence-Rydberg mixed nature, while that of CF3Cl is of a predominant Câ€"Cl antibonding character. A comparison with the experimental GOSs of CH3Cl provides unambiguous evidence that the 3pe state is lower in energy than the 3pa1 state. Optical oscillator strengths are also calculated and comparison is made with available experimental and other theoretical results. [ABSTRACT FROM AUTHOR]

The spectral parameters (energy levels, wavelengths, transition probabilities, line strengths, and oscillator strengths) of resonance lines for Ba VIII, La IX, and Ce X have been obtained using the multiconfiguration Dirac–Hartree–Fock method, with contributions of quantum electrodynamics and Breit interaction corrections taken into consideration. The calculated results of energy levels and wavelengths are in good agreement with experimental values and other calculations. The number of energy levels and wavelengths considered is larger than that of any other experiment or other calculations. The transition probabilities, line strengths, and oscillator strengths are also calculated where no other theoretical results and experimental values are available. [ABSTRACT FROM AUTHOR]

Analysis of variance (ANOVA) is the most used procedure for comparing means between different groups. However, in some cases, disregarding the assumptions of ANOVA can lead to spatial dependence. In such cases, to ensure greater experimental precision, it is necessary to consider the study of spatial dependence. This study was carried out to compare the estimates of experimental precision of the traditional analysis of variance with those of the analysis of variance using an autoregressive (ANOVA-AR) model in corn experiments under different N conditions when evaluating grain yield. Data were obtained from 14 experiments using lattice designs conducted in 2012, 2014, and 2015 in the following counties in the Brazilian state of Mato Grosso do Sul: Caarapó, Dourados, Glória de Dourados, and Laguna Carapã. Of the 14 experiments, 7 were performed with N fertilization (ideal) and 7 experiments were performed under stressful conditions (zero or low). Both analyses were compared by considering estimates of reduction of the error mean square, coefficient of determination, F-value, and selective accuracy as well as the difference in the order of 25% of the genotypes of each experiment (from 13 to 56 genotypes, considering the size of the experiment). Differences in the error mean square and genotype mean square were slightly more evident in 1, 2, 3, 4, 5, 6, and 11 experiments but the use of ANOVA-AR did not promote major changes. The analysis of variance with an autoregressive model provided parameter values of experimental precision similar to those expressed by traditional analysis of variance. There was no difference in terms of correlated errors in experiments under different N conditions. [ABSTRACT FROM AUTHOR]

In this work, we present two different methods for calculation of the atomic structure for atoms and ions. The first one is the Hartree‐Fock pseudo‐Relativistic method which can be ab initio where we calculate the atomic parameters theoretically by using, for example, the first three programs of the Cowan (CW) atomic structure code: RCN, RCN2, and RCG. We can also use it semi‐empirically by using the fourth CW program RCE and fitting the purely theoretical energy levels with experimental data taken for example from the NIST database. The second one is the Thomas‐Fermi‐Dirac‐Amaldi method which can be ab initio where we calculate the atomic parameters theoretically by using, for example, the SUPERSTRUCTURE (SS) or the AUTOSTRUCTURE (AS) atomic structure codes. We can also use it semi‐empirically by using the Term Energy Corrections in SS or the Level Energy Corrections in SS or AS atomic structure codes. As an application of using these methods, we calculate energy levels, oscillator strengths, and transition probabilities for the 5p‐6s transitions for the Mo II ion using ab initio and semi‐empirical methods with the CW and AS atomic structure codes. [ABSTRACT FROM AUTHOR]

In this work, energy levels, oscillator strengths, and transition probabilities for the Ti II ion are calculated by the Hartree–Fock pseudo‐Relativistic method using the Cowan (CW) atomic structure code and by the Thomas‐Fermi‐Dirac‐Amaldi method using the AUTOSTRUCTURE (AS) atomic structure code. We used the terms and levels generated by the 12 configurations: 3d2 ns (n = 4–6), 3d2 np (n = 4,5), 3d2 nd (n = 4,5), 3d2 4f, 3d 4s np (n = 4,5), 3d 4s2, 3d3. We improved our ab initio calculated data by using the semi‐empirical methods in the CW and AS atomic structure codes. We also compared them with other theoretical and experimental results and obtained new data for this ion. [ABSTRACT FROM AUTHOR]

Metal‐based thermally activated delayed fluorescence (TADF) is conceived to inherit the advantages of both phosphorescent metal complexes and purely organic TADF compounds for high‐performance electroluminescence. Herein a panel of new TADF Au(I) emitters has been designed and synthesized by using carbazole and pyrazine‐fused nitrogen‐heterocyclic carbene (NHC) as the donor and acceptor ligands, respectively. Single‐crystal X‐ray structures show linear molecular shape and coplanar arrangement of the donor and acceptor with small dihedral angles of <6.5°. The coplanar orientation and appropriate separation of the HOMO and LUMO in this type of molecules favour the formation of charge‐transfer excited state with appreciable oscillator strength. Together with a minor but essential heavy atom effect of Au ion, the complexes in doped films exhibit highly efficient (Φ∼0.9) and short‐lived (<1 μs) green emissions via TADF. Computational studies on this class of emitters have been performed to decipher the key reverse intersystem crossing (RISC) pathway. In addition to a small energy splitting between the lowest singlet and triplet excited states (ΔEST), the spin‐orbit coupling (SOC) effect is found to be larger at a specific torsion angle between the donor and acceptor planes which favours the RISC process the most. This work provides an alternative molecular design to TADF Au(I) carbene emitters for OLED application. [ABSTRACT FROM AUTHOR]

Studies on brain mechanisms enable us to treat various brain diseases and develop diverse technologies for daily life. Therefore, an analysis method of neural signals is critical, as it provides the basis for many brain studies. In many cases, researchers want to understand how neural signals change according to different conditions. However, it is challenging to find distinguishing characteristics, and doing so requires complex statistical analysis. In this study, we propose a novel analysis method, FTF (F-value time-frequency) analysis, that applies the F-value of ANOVA to time-frequency analysis. The proposed method shows the statistical differences among conditions in time and frequency. To evaluate the proposed method, electroencephalography (EEG) signals were analyzed using the proposed FTF method. The EEG signals were measured during imagined movement of the left hand, right hand, foot, and tongue. The analysis revealed the important characteristics which were different among different conditions and similar within the same condition. The FTF analysis method will be useful in various fields, as it allows researchers to analyze how frequency characteristics vary according to different conditions. [ABSTRACT FROM AUTHOR]

Motivated by the controversy over the surface metallicity of the Sun, we present a re-analysis of the solar photospheric oxygen (O) abundance. New atomic models of O and Ni are used to perform non-local thermodynamic equilibrium (NLTE) calculations with 1D hydrostatic (MARCS) and 3D hydrodynamical (Stagger and Bifrost) models. The Bifrost 3D MHD simulations are used to quantify the influence of the chromosphere. We compare the 3D NLTE line profiles with new high-resolution, R |$\approx 700\, 000$|⁠ , spatially resolved spectra of the Sun obtained using the IAG FTS instrument. We find that the O  i lines at 777 nm yield the abundance of log  A (O) = 8.74 ± 0.03 dex, which depends on the choice of the H-impact collisional data and oscillator strengths. The forbidden [O  i ] line at 630 nm is less model dependent, as it forms nearly in LTE and is only weakly sensitive to convection. However, the oscillator strength for this transition is more uncertain than for the 777 nm lines. Modelled in 3D NLTE with the Ni  i blend, the 630 nm line yields an abundance of log  A (O) = 8.77 ± 0.05 dex. We compare our results with previous estimates in the literature and draw a conclusion on the most likely value of the solar photospheric O abundance, which we estimate at log  A (O) = 8.75 ± 0.03 dex. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the influence of hierarchical relationships on interests failed to consider in the existing micro-blog recommendation, this paper proposed a micro-blog recommendation algorithm base on hierarchical social relationships. Firstly, it calculated the relative intimacy intensity and social growth rate based on the time window to construct a hierarchical network. Secondly, it quantified influence, attractiveness, and closeness of interaction in the network to tap the potential interest of target users. Then, it obtained the explicit interest of target users based on short text expansion strategy. Finally, it integrated potential interest with explicit interest, calculated the similarity between the fused interest and the micro-blog to be recommended to achieve recommendation. The experimental results show that compared with the classic micro-blog recommendation method, the new method is better than other methods in accuracy, recall, F-value, and MRR, with a maximum increase of 14.73%.The experimental results show that comprehensive consideration of potential interest and explicit interest can improve the effect of micro-blog recommendation. [ABSTRACT FROM AUTHOR]

We have theoretically determined the absorption oscillator strengths and wavenumbers for rotationally resolved transitions of the c4′1ÎŁu+ (6)-X1ÎŁg+(0â€"9) bands of N2, which are relevant to analyze the spectra of planetary atmospheres. The Molecular Quantum Defect Orbital method has been used in our calculations. The interaction between the c4′1ÎŁu+ (6) Rydberg state and the b′1ÎŁu+ valence states has been considered using an adequate rovibronic energy matrix. In addition, we have calculated the lifetimes of the rotational levels of the c4′1ÎŁu+ (6) state. We hope that the reported data, most of them for the first time, can be useful in the interpretation of planetary atmospheres where N2 is present. [ABSTRACT FROM AUTHOR]

Extraction is the most costly and complicated stage of timber harvest operations. The forwarder's productive capacity in timber harvesting, from planted forests, is influenced by several operational variables, especially by extraction distance and tree volume. Prior knowledge about the effect of these variables on the operation is required for efficient planning. The goal of this research was to model and simulate a forwarder productivity curve for timber extraction in scenarios with different tree average volumes (TAV) and average extraction distances (AED). The research was carried out in a forestry company in the state of Mato Grosso do Sul, Brazil, in clonal eucalyptus stands with TAV varying from 0.186 to 0.310 m3 tree−1 and AED from 0 to 280 m. We performed a time and motion study of the forwarder, following the operation with a DJI-Phantom 4 Advanced drone. Productivity simulations were carried out in different operational scenarios. The models were evaluated using the adjusted determination coefficients (R2 adj.), standard error of absolute estimate and F-value. Results have shown that as the TAV increased, productivity also increased 14% while the AED presented a relationship inversely proportional to productivity. The highest productivity of the machine occurred in the forest condition with a TAV of 0.31 to 0.36 m3 tree−1 and in the shortest extraction distances. The best-adjusted model explained 46.3% of the machine's productivity variation. We concluded that TAV and AED variables had a significant impact on the forwarder's productivity and that it is important to obtain the machine's productivity curves for efficient forest operations planning. [ABSTRACT FROM AUTHOR]

We have theoretically determined the absorption oscillator strengths and wavenumbers for rotationally resolved transitions of the c4′1ÎŁu+ (6)-X1ÎŁg+(0â€"9) bands of N2, which are relevant to analyze the spectra of planetary atmospheres. The Molecular Quantum Defect Orbital method has been used in our calculations. The interaction between the c4′1ÎŁu+ (6) Rydberg state and the b′1ÎŁu+ valence states has been considered using an adequate rovibronic energy matrix. In addition, we have calculated the lifetimes of the rotational levels of the c4′1ÎŁu+ (6) state. We hope that the reported data, most of them for the first time, can be useful in the interpretation of planetary atmospheres where N2 is present. [ABSTRACT FROM AUTHOR]

In this work, we present a series of benchmark variational calculations for the ground and 19 lowest bound excited singlet S and P states of the beryllium atom. The nonrelativistic wave functions of the states that represent the motion of the nucleus and the four electrons around the center of mass of the atom are expanded in terms of up to 17 000 all-particle explicitly correlated Gaussians. The Gaussians are optimized independently for each state. The leading relativistic corrections to the energy levels are computed in the framework of the perturbation theory and they explicitly include the nuclear recoil effects. We also calculate the leading quantum electrodynamics (QED) corrections for each considered state. Using the obtained energy levels and the corresponding wave functions, we compute the transition frequencies, transition dipole moments, and oscillator strengths. A comparison with the available experimental data shows very good agreement. The results of this most comprehensive set of calculations of spectroscopic accuracy for Be to date may open up new applications pertinent to the precision tests of QED, determination of the nuclear charge radius, and modeling matter-radiation equilibria of the beryllium gas that has relevance to the physics of interstellar media. [ABSTRACT FROM AUTHOR]

Friction in carbon nanotube (CNT) oscillators can be explained in terms of the interplay between low frequency mechanical motions and high frequency vibrational modes of the sliding surfaces. We analyze single mode phonon wave packet dynamics of CNT based mechanical oscillators, with cores either stationary or sliding with moderate velocities, and study how various individual phonons travel through the outer CNT, interact with the inner nanostructure, and undergo scattering. Two acoustic modes (longitudinal and transverse) and one optical mode (flexural optical) are found to be responsible for the major portion of friction in these oscillators: the transmission functions display a significant dip in the rather narrow frequency range of 5-15 meV. We also find that the profile of the dip is characteristic of the inner core. In contrast, radial breathing and twisting modes, which are dominant in thermal transport, display ideal transmission at all frequencies. We also observe polarization dependent scattering and find that the scattering dynamics comprises of an oscillating decay of localized energy inside the inner CNT. This work provides a way towards engineering CNT linear oscillators with better tribological properties. [ABSTRACT FROM AUTHOR]

The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities. [ABSTRACT FROM AUTHOR]

Second-harmonic generation (SHG) is a non-linear optical process, where two photons coherently combine into one photon of twice their energy. Efficient SHG occurs for crystals with broken inversion symmetry, such as transition metal dichalcogenide monolayers. Here we show tuning of non-linear optical processes in an inversion symmetric crystal. This tunability is based on the unique properties of bilayer MoS2, that shows strong optical oscillator strength for the intra- but also interlayer exciton resonances. As we tune the SHG signal onto these resonances by varying the laser energy, the SHG amplitude is enhanced by several orders of magnitude. In the resonant case the bilayer SHG signal reaches amplitudes comparable to the off-resonant signal from a monolayer. In applied electric fields the interlayer exciton energies can be tuned due to their in-built electric dipole via the Stark effect. As a result the interlayer exciton degeneracy is lifted and the bilayer SHG response is further enhanced by an additional two orders of magnitude, well reproduced by our model calculations. Since interlayer exciton transitions are highly tunable also by choosing twist angle and material combination our results open up new approaches for designing the SHG response of layered materials. Efficient second-harmonic generation (SHG) occurs for crystals with broken inversion symmetry, such as transition metal dichalcogenide monolayers. Here the authors show SHG tuning in bilayer MoS2 - an inversion-symmetric crystal - mediated by interlayer excitons. [ABSTRACT FROM AUTHOR]

Engineering a low singlet-triplet energy gap (ΔEST) is necessary for efficient reverse intersystem crossing (rISC) in delayed fluorescence (DF) organic semiconductors but results in a small radiative rate that limits performance in LEDs. Here, we study a model DF material, BF2, that exhibits a strong optical absorption (absorption coefficient = 3.8 × 105 cm−1) and a relatively large ΔEST of 0.2 eV. In isolated BF2 molecules, intramolecular rISC is slow (delayed lifetime = 260 μs), but in aggregated films, BF2 generates intermolecular charge transfer (inter-CT) states on picosecond timescales. In contrast to the microsecond intramolecular rISC that is promoted by spin-orbit interactions in most isolated DF molecules, photoluminescence-detected magnetic resonance shows that these inter-CT states undergo rISC mediated by hyperfine interactions on a ~24 ns timescale and have an average electron-hole separation of ≥1.5 nm. Transfer back to the emissive singlet exciton then enables efficient DF and LED operation. Thus, access to these inter-CT states, which is possible even at low BF2 doping concentrations of 4 wt%, resolves the conflicting requirements of fast radiative emission and low ΔEST in organic DF emitters. A low singlet-triplet energy gap, necessary for delayed fluorescence organic semiconductors, results in a small radiative rate that limits performance in OLEDs. Here, the authors show that it is possible to reconcile these conflicting requirements in materials that can access both high oscillator strength intramolecular excitations and intermolecular charge transfer states. [ABSTRACT FROM AUTHOR]

We have implemented pseudospectral density‐functional theory (DFT) with long‐range corrected DFT functionals (PS‐LRC) in quantum mechanics package Jaguar, and applied it in the calculations of geometry optimizations, dimmer interaction energies, polarizabilities and first‐order hyperpolarizabilities, harmonic vibrational frequencies, S1 and T1 excitation energies, singlet‐triplet gaps, charge transfer numbers, oscillator strengths, reaction barrier heights, electron‐transfer couplings, and charge‐transfer excitation energies. From our accuracy benchmark analysis, PS grids, PS dealiasing functions, PS atomic corrections, PS multigrid strategy, PS length scales, and PS cutoff scheme perform well in PS DFT with LRC density functionals with very small and ignorable deviations when compared to the conventional spectral (CS) method. The timing benchmark study of S1 excitation energy calculations of fullerenes (Cn, n up to 540) demonstrates that PS‐LRC achieves 1.4–8.4‐fold speedups in SCF, 22–32‐fold speedups in Tamm‐Dancoff approximation, and 6–15‐fold speedups in total wall clock time with an average error 0.004 eV of excitation energies compared to the CS method. [ABSTRACT FROM AUTHOR]

Consumers purchasing textiles usually feel fabrics for its tactile properties indicating that they are interested in comfort properties rather than other properties. During daily activities, low-stress mechanical action like bending, shear, compression, tensile, and hysteresis occurs on clothing. These high sensitive low-stress mechanical properties have influence on movement comfort of the body. This study reports effect of cotton yarn parameters on tactile comfort and low-stress mechanical properties of four knitted fabrics. These fabrics were developed with cotton yarn having different yarn counts; twist, coefficient of mass variation, neps, hairiness, thin and thick places, and strength and elongation. Half-bleach treatment was carried out on the knitted fabrics and the effect of yarn parameters plus their correlation on tactile comfort and low-stress mechanical properties were evaluated. Results statistically analyzed showed that coefficient of friction, surface roughness, tensile, bending, shear, and compression of knitted fabrics were affected by yarn count. However, in wales direction, tensile resilience (RT%) of knitted fabrics had insignificant change with an F-value of 1.110 and p-value of.248. A correlation was also found between fabric smoothness and yarn count at adj. R2 = 83.1%. A relationship between yarn parameters and tactile comfort properties was also modeled using equations. [ABSTRACT FROM AUTHOR]

We have calculated the energy levels, oscillator strengths, and transition probabilities for eight carbon-like ions (Na  vi , Mg  vii , Al  viii , Si  ix , P  x , S  xi , Cl  xii and Ar  xiii) using the Hartree–Fock pseudo-relativistic (HFR) and Thomas–Fermi–Dirac–Amaldi (TFDA) approaches. We used configuration expansions containing eight configurations, namely 2s2 2p2, 2s 2p3, 2s2 2p 3s, 2s2 2p 3p, 2s2 2p 3d, 2s2 2p 4s, 2s2 2p 4p, and 2s2 2p 5s. For each of the considered ions we obtained 59 energy levels, a number of which are not in the National Institute of Standards and Technology (NIST) data base. We compared our results with critically selected experimental data from NIST and with calculations made using the multiconfiguration Hartree–Fock (MCHF) method. We calculated weighted oscillator strengths and transition probabilities using two methods (HFR and TFDA) for the 2s2 2p2 and 2s 2p3 configurations for the eight C-like ions considered here. We analysed the atomic structure parameter trends, which allowed us to find missing data belonging to an isoelectronic sequence. The energy levels, oscillator strengths, and transition probabilities calculated here are in good agreement with the data from the NIST data base. Because emission and absorption features from C-like ions are often used for density and temperature diagnostics of various plasmas in astrophysics, and in studies of the solar corona, including solar flares, and of the coronae of other stars and of ionized outflows in active galactic nuclei etc. the obtained data will be useful for improving plasma diagnostics and modelling, in particular for the X-ray Universe. [ABSTRACT FROM AUTHOR]

In this study, the methylene bis(dithiobenzoate) molecule, (C15H12S4), as a bioactive molecule has been subjected to quantum chemical computations using density functional theory (DFT) in order to investigate the molecular geometry, IR, UV-visible and NMR spectral studies. The title molecule has been optimized at the B3LYP, B3PW91 and PBE1PBE levels of DFT and 6-311G(d,p) basis set. Furthermore, the vibrational frequencies, the HOMO–LUMO energy levels, the 1H and 13C NMR chemical shifts (ppm), nonlinear optical properties calculations of the title compound were obtained by B3LYP, B3PW91 and PBE1PBE levels. The maximum electronic transition wavelengths, oscillator strengths, excited state and transition dipole moments for the title compound were also investigated by B3LYP, B3PW91 and PBE1PBE levels of time-dependent TD-DFT. [ABSTRACT FROM AUTHOR]

The transition energies, E1 transitional oscillator strengths of the spin-allowed as well as the spin-forbidden and the corresponding transition rates, and complete M1, E2, M2 forbidden transition rates for 1 s 2, 1 s 2 s, and 1 s 2 p states of He I, are investigated using the multi-configuration Diracâ€"Hartreeâ€"Fock method. In the subsequent relativistic configuration interaction computations, the Breit interaction and the QED effect are considered as perturbation, separately. Our transition energies, oscillator strengths, and transition rates are in good agreement with the experimental and other theoretical results. As a result, the QED effect is not important for helium atoms, however, the effect of the Breit interaction plays a significant role in the transition energies, the oscillator strengths and transition rates. [ABSTRACT FROM AUTHOR]

The methyl orange [C14H14N3SO3Na], an azo dye exhibited strong emission and large Stokes shift in various solvents, and the largest shift (Δλ = 125.51nm or Δν = 9297cm-1) was obtained in the water. The UV-visible spectra of the dye showed the absorption in the range (33,333 – 20,000) cm-1. We found that solvent effects on the absorption wavelength are consistent. The bathochromic shift in water and the hypsochromic shift in methanol observed in the absorption (43 nm) as well as in the fluorescence (42 nm) spectra predict the strong solute-solvent interaction. The fluorescence quantum yield (ɸf) was decreased from 24% in DMSO to 5% in water. The fluorescent properties of this dye are strongly solvent dependent, the wavelength of minimum fluorescence emission (λem = 435.51nm) shifts to the red. The maximum and minimum calculated oscillator strength is 32% with (Ɛmax = 29011 M-1cm-1) and 11% (Ɛmax = 6682 M-1cm-1) in methanol and DMSO, respectively. Protonated solvents without exception give a shorter lifetime and lower quantum yield. The average excited-state lifetime of the dye was found maximum (τav = 5.36 ns) in DMSO. Also, fluorescence lifetime was combined to deduce the radiative and non-radiative decay rate. [ABSTRACT FROM AUTHOR]

Thermally activated delayed fluorescence (TADF) materials with through‐space charge transfers (CT) have attracted particularly interest recently. However, the slow reverse intersystem crossing (RISC) and radiative decay always limit their electroluminescence performances. Herein, TADF molecules with ortho‐linked multiple donors‐acceptor (ortho‐Dn‐A) motif are developed to create near‐degenerate excited states for the reinforcement of spin‐orbit coupling. The incorporation of both through‐bond and through‐space CT enlarges oscillator strength. The optimal ortho‐D3‐A compound exhibits a photoluminescence quantum yield of ca. 100 %, a high RISC rate of 2.57×106 s−1 and a high radiative decay rate of 1.00×107 s−1 simultaneously. With this compound as the sensitizer, a TADF‐sensitized‐fluorescent organic light‐emitting diode shows a maximum external quantum efficiency of 31.6 % with an ultrapure green Commission Internationale de L'Eclairage y coordinate value of 0.69. [ABSTRACT FROM AUTHOR]

Rationally manipulating the functional substituents plays a crucial role in tuning the luminescence and lasing properties of organic gain media. Herein, a cyanophenyl‐moiety, which exhibits relatively weaker electron affinity, is connected to 2,6‐dicarbonitrile diphenyl‐1λ5‐phosphinine (DCNP) via para‐linking. Resultantly, the appreciated locally‐excited characteristics ensuring a large oscillator strength and high radiative rate can be reserved in DCNP‐4‐(4‐cyanophenyl) (DCNP‐pCN). Interestingly, the weak charge‐transfer state from the relative donor (D)/acceptor (A) interplay enables small singlet‐triplet splitting (ΔEST ≈ 0.45 eV). Thus the triplets generated on DCNP‐pCN can be efficiently scavenged by 4,4'‐bis[(N‐carbazole)styryl]biphenyl (BSBCz), which is used as the host with a lower‐lying triplet energy level for DCNP‐pCN. Moreover, benefitting from the mediation between the conjugated length extension and weak D/A interplay, the emission spectrum cannot be largely shifted, which can effectively suppress the overlap between the lasing emission of DCNP‐pCN and the excited‐state absorption of BSBCz, thereby avoiding detrimental singlet‐triplet annihilation. Thus, high‐quality distributed feedback lasings with ≈2.0 μJ cm−2 thresholds are achieved, and the organic light‐emitting diodes exhibit external quantum efficiency exceeding 2.0% without efficiency rolloff under high current injection, indicating the potential for electrical‐pumping organic lasings. [ABSTRACT FROM AUTHOR]

Semiconducting quantum dots (SQDs) are attractive materials for optoelectronic applications due to the size‐tunable band gaps, colloidal stability, and low‐cost solution processability. In this article, we investigate the modulations in the optical features of COOH + NH3 capped tetrahedral‐shape CdSe SQD in response to the external electric field. We base our calculations on an approach which combines the linear combination of atomic orbitals (LCAO) real‐time‐propagation‐time‐dependent density functional theory (rt‐TDDFT) technique (LCAO‐rt‐TDDFT) and transition contribution maps (two‐dimensional visualization of Kohn–Sham single electron–single hole transitions). Among other insights, our study indicates that electric field causes a redistribution of the oscillator strengths, early onset of absorption, and ligand‐derived trap states near the top of the valence band. These theoretical findings explain the origins of the electric field induced optical features of ligated SQDs. [ABSTRACT FROM AUTHOR]

Energy levels, Einstein A -values, and oscillator strengths are calculated for doubly ionized germanium (Ge  iii). We have undertaken a study of the electron-impact excitation of Ge  iii and have also completed a study of the photoionization of Ge  ii. Ge  iii target structures were generated using the relativistic  grasp0 package. Several scattering models were investigated to assess the uncertainty quantification of our results. Initially, the lowest lying 64 jj fine-structure levels were included in the close-coupling expansion resulting from 14 non-relativistic configurations. A second larger model was subsequently generated using the gasp package and incorporated the lowest 589 jj fine-structure levels from 17 non-relativistic configurations. Both the DARC (Dirac atomic R-matrix code) and Breit–Pauli parallel suite of R-matrix collision codes were utilized in the scattering calculations to generate the collision strengths for incident electron energies between 0 and 5 Rydbergs and subsequently the Maxwellian-averaged effective collision strengths for temperatures in the range of 1000–200 000 K. The photoionization calculations comprised of two studies, a DARC and a Breit–Pauli calculation incorporating the 250 lowest lying levels. Photoionization cross-sections for Ge  ii are presented in the range of 0–5 Ryds. Due to the lack of data available in the literature, the present radiative data and electron-impact/photoionization cross-sections are compared between the models presented in this paper. To assess their significance for astrophysics, the data are incorporated into the stellar atmosphere package sterne. Test models for the heavy-metal subdwarf LS IV−14○116 are not affected by the new data, but models for cooler stars may be sensitive to them. [ABSTRACT FROM AUTHOR]

With the rapid development of Internet, the medical Q&A community has become an important channel for people to obtain and share medical and health knowledge. Online medical entity recognition (OMER), as the foundation of medical and health information extraction, has attracted extensive attention of researchers in recent years. In order to further improve the research progress of Chinese OMER, LSTM-Att-Med model is proposed in this paper to capture more external semantic features and important information. First, Word2vec is used to generate the character- level vectors with semantic features on the basis of the unlabeled corpus in the medical domain and open domain respectively. Then, the two character-level vectors are embedded into BiLSTM-CRF as features to construct LSTM-Wiki and LSTMMed models. Finally, Self-Attention mechanism is introduced into LSTM-Med model, and the performance of the model is validated by using the self-labeled data. The 10-fold cross-validation experiment shows that LSTM-Att-Med with Self-Attention mechanism introduced achieves the best performance and the F-value can be up to 91.66%, which is 0.72% higher than that of BiLSTM-CRF. In addition, the experiment result demonstrates that the improvements of F-value are inconsistent for different corpora based on LSTM-Att-Med. The paper also analyzes the recognition performance and error results of different medical entities. [ABSTRACT FROM AUTHOR]

In this work, ten metal-free organic dyes based on the 4,4′-dimethoxy triphenylamine donor and cyanoacrylic acid acceptor were designed and computationally studied for their potential in DSSC. The different π-spacers employed for the comparative study are benzothiadiazole (TC1), quinoxaline (TC2), benzotriazole (TC3), phenathrothiadiazole (TC4) and dihexylcyclopentadithiophene (TC5). The 4,4′-dimethoxy triphenylamine donor was paired with the π-spacers via single-bond/double-bond joints. This computational work mainly aims at determining the impact of the π-spacer on the geometrical and optoelectronic properties using the Density Functional Theory (DFT) and Time-Dependent-DFT approaches. Our studies revealed that all of the designed dyes have strong absorptions in the range of 560–700 nm with satisfactory oscillator strengths and light-harvesting efficiencies (LHE). Several other photovoltaic parameters, such as absorption maximum, driving force for dye regeneration (Greg), energy level alignment, chemical reactivity parameters, reorganization energy, and dye adsorption energy (Eads), were measured to determine the role of heterocyclic π-spacers in improving the efficiency of a solar cell. Based on the above parameters, the dye with benzothiadiazole spacer was identified to be the most promising candidate among those studied. These findings provide valuable hints for the fast screening of π-spacers for the efficient molecular engineering of organic sensitizers. [ABSTRACT FROM AUTHOR]

Recently, numerous efforts have been devoted to sky blue or greenish blue organic light-emitting diodes (OLEDs), nevertheless, the deep blue and pure blue OLEDs still remain a formidable challenge. Herein, a series of deep blue and pure blue donor–acceptor–donor (D–A–D) type emitters, namely Cz-DMTD, PhCz-DMTD and TMCz-DMTD, were constructed. For PhCz-DMTD which exhibited no delayed fluorescence component, the extended delocalization of donors and the enhancement of oscillator strength were both observed through theoretical calculation. For methyl-engineered TMCz-DMTD, the degenerate charge transfer singlet excited (1CT) and triplet excited (3CT) states and localized triplet excited (3LE) state endowed a thermally activated delayed fluorescence (TADF) character. Moreover, PhCz-DMTD and TMCz-DMTD based OLEDs displayed emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.164, 0.077) and (0.157, 0.107) and with maximum external quantum efficiencies (EQEmax) of 4.6% and 8.7%, respectively. It is the first time that the electroluminescence wavelength of TMCz based OLEDs reached below 450 nm with a CIEy below 0.11. Molecular engineering of the carbazole moiety is expected to provide a valuable strategy for molecular design of more deep blue emitters. [ABSTRACT FROM AUTHOR]

We investigated isolated 2-hydroxypyrene and its dimer in the gas phase by time- and frequency-resolved photoionisation with picosecond time-resolution. The experiments are supported by simulations that include an extensive conformational search based on the machine learning ANI-1ccx neural network potential combined with automatic structure classification using a data clustering algorithm. Vibrationally resolved spectra of the S1 ← S0 and S2 ← S0 transitions are reported which are in very good agreement with the simulated spectra at the TDDFT level. As expected from the molecular orbitals involved in the transitions, the red-shifts of the transitions are more pronounced for the S1 state compared to those of unsubstituted pyrene. While a ns-lifetime is observed for the S1 state, the lifetime decreases to 3 ps or less for the origin of the S2 state, indicating a strong interaction between the two states. For the dimer, a slightly V-shaped structure was computed, and intermolecular interactions are dominated by dispersion rather than hydrogen-bonding. The highest oscillator strength was computed for the transition to the S4 state, which deactivates within 4 ps to a lower-lying excited state. [ABSTRACT FROM AUTHOR]

Organic solar cells are approaching power conversion efficiencies of other thin‐film technologies. However, in order to become truly market competitive, the still substantial voltage losses need to be reduced. Here, the synthesis and characterization of four novel arylamine‐based push‐pull molecular donors was described, two of them exhibiting a methyl group at the para‐position of the external phenyl ring of the arylamine block. Assessing the charge‐transfer state properties and the effects of methylation on the open‐circuit voltage of the device showed that devices based on methylated versions of the molecular donors exhibited reduced voltage losses due to decreased non‐radiative recombination. Modelling suggested that methylation resulted in a tighter interaction between donor and acceptor molecules, turning into a larger oscillator strength to the charge‐transfer states, thereby ensuing reduced non‐radiative decay rates. [ABSTRACT FROM AUTHOR]

The aim of this work is to provide energy level calculations among the lowest 71 levels arising out of 1 s 2 and 1snl ( n ≤ 6 , l ≤ (n - 1) ) configurations of He-like lithium. The calculations are carried out through the relativistic configuration interaction approach and the second-order many-body perturbation theory implemented in the flexible atomic code. We provide accurate calculations of energy levels, lifetimes, wavelengths, weighted oscillator strengths and radiative rates for the allowed (E1) transitions of He-like lithium. We have also considered relativistic effects by incorporating quantum electrodynamics and Breit corrections. The radiative lifetimes are reported for all the calculated levels. The present results are in good agreement with the previous results in literature (theoretical and experimental data). Several new energy levels and wavelengths were found out where no other theoretical or experimental results are available. We expect that our extensive calculations will be useful to experimentalists for identifying the fine-structure levels. [ABSTRACT FROM AUTHOR]

This paper deals with the optical and photophysical properties of dihydrophenanthro[9,10-e][1,2,4]triazine fluorescent dyes doped in Silicate based sol–gel and homo-poly methyl methacrylate (PMMA). Solid hosts were found to effect on the optical and photophysical parameters such as molar absorptivity, cross sections of singlet–singlet electronic absorption and emission spectra, excited state lifetime, quantum yield of fluorescence. The dipole moment of electronic transition, the length of attenuation and oscillator strength of electronic transition from So → S1 have been calculated. The dyes were pumped with different powers using 3rd harmonic Nd:YAG laser of 355 nm and pulse duration 8 ns, with a repetition rate at (10 Hz). Good photostability for compounds 1 and 2 were attained. It was decreased to 49% & 54% and 46% & 40% of the initial ASE of dyes in sol gel and PMMA, respectively, after 55,000 pumping pulses at (10 mJ/pulse). The dyes in sol–gel showed improved photostability compared with those in organic polymeric matrices. [ABSTRACT FROM AUTHOR]