Partial Contributions Research Articles

A combined experimental and theoretical study of photodouble ionization of water at 32 eV excess energy and unequal energy sharing

The photodouble ionization of water at about 32 eV excess energy has been investigated both experimentally and theoretically. In an energy and angular resolved photoelectron–photoelectron coincidence experiment, the two photoelectrons in unequal energy sharing (25 and 7 eV) condition, have been detected in a plane perpendicular to the propagation direction of the linearly polarized radiation. The measured angular distributions have been compared with, molecular orientation averaged, triple differential cross sections calculated with a recently developed theoretical model (Randazzo et al 2020 Phys. Rev. A 101 033407). The model uses separable products of orbitals as initial electronic state of the water molecule taken as a two-electron target and describes accurately the correlated two electron continuum. The combination of calculated cross sections corresponding to different dication states capture most of the measured features in terms of the evolution of both the shape and the intensity as a function of the faster electron direction which is set at 0°, 30° and 60° with respect to the polarization vector of the incident radiation. A detailed analysis in terms of the different dication states as well as of the partial wave contributions to the electron pair wave function sheds light on the origin of such features.

An Analysis of the Water-to-Ice Phase Transition Using Acoustic Plate Waves.

It is shown that, in spite of the wave radiation into the adjacent liquid, a large group of Lamb waves are able to propagate along piezoelectric plates (quartz, LiNbO3, LiTaO3) coated with a liquid layer (distilled water H2O). When the layer freezes, most of the group’s waves increase their losses, essentially forming an acoustic response towards water-to-ice transformation. Partial contributions to the responses originating from wave propagation, electro-mechanical transduction, and wave scattering were estimated and compared with the coupling constants, and the vertical displacements of the waves were calculated numerically at the water–plate and ice–plate interfaces. The maximum values of the responses (20–30 dB at 10–100 MHz) are attributed to the total water-to-ice transformation. Time variations in the responses at intermediate temperatures were interpreted in terms of a two-phase system containing both water and ice simultaneously. The results of the paper may turn out to be useful for some applications where the control of ice formation is an important problem (aircraft wings, ship bodies, car roads, etc.).

An examination of the tail contribution to distortion risk measures

Extreme losses are specially relevant in the finance and insurance sectors. Here, we analyze the tail behavior of risks and its influence on risk measures. Specifically, we examine the part of the risk value of a distortion risk measure (DRM) that is attributable to extreme losses. We analyze the additive properties of tail contributions to risk values when several risks are aggregated. We show that the partial contributions are subadditive if the distortion function is concave in the tail. We examine the tail behavior for quantile-based DRMs, including value-at-risk and tail value-at-risk. We conclude that such an evaluation will allow decision makers to obtain relevant information about the contribution of extreme losses to risk values and about the fraction of the diversification benefit attributable to the tails. An example is used to illustrate our results.

The Intrinsic and Extrinsic Effects of Tet Proteins During Gastrulation

Mice deficient for all Ten-eleven translocation (TET) genes exhibit early gastrulation lethality. Yet, separating cause and effect in such embryonic failure is challenging. To isolate cell-autonomous effects of TET loss, we used temporal single-cell atlases from embryos with partial or complete mutant contributions. Strikingly, when developing within a wild-type embryo, TET mutant cells retain near-complete differentiation potential, while embryos solely comprised of mutant cells are defective in epiblast to ectoderm transition with degenerated mesoderm potential. We map de-repressions of early epiblast factors and failure to activate signaling from nascent mesoderm as intrinsic drivers of TET phenotypes. We further suggest near-complete loss of enhancer demethylation as a possible mechanism for mis-regulation in TET deficient cells. Collectively, our work demonstrates an unbiased approach for defining intrinsic and extrinsic embryonic gene function based on temporal differentiation atlases, and disentangles the intracellular effects of the demethylation machinery from its broader tissue-level ramifications.

Indicator variables for inflation expectations in the Euro area

In this paper, we model the Euro area market-based inflation expectations extracted from the inflation-linked swaps, and study the macroeconomic information embedded in expected inflation. First, we estimate the Gaussian affine term structure model to decompose the forward ILS-implied inflation rate into inflation expectations and inflation risk premium at one-, two- and three-year horizons. Secondly, from a large panel of macroeconomic series we identify the most significant indicator variables for inflation expectations using the elastic net modification of the LASSO regression. Finally, we measure partial contributions of individual indicator variables to the changes in inflation expectations. Our findings reveal that across horizons considered inflation expectations are correlated to the measures of current inflation of the overall price level and price level of services, the unemployment rate, and the Euro exchange rate. The identified indicators provide a useful information about the evolution of inflation expectations with different intensities at different horizons.

Predikcija mentalne jačine sportista na osnovu osobina ličnosti

The aim of this research is to examine the connection between mental toughness of athletes and their personality traits. The research sample consists of 100 athletes who participate in sports competitions. Mental Toughness was measured by Sports Mental Toughness Questionnaire (SMTQ), HEXACO personality traits by HEXACO-60. The results showed statistically significant positive correlations between honesty on one side and self-confidence (r= 0,31, p<0,01), consistency (r= 0,45, p<0,01), control (r= 0,34, p<0,01) and overall mental toughness (r= 0,46, p<0,01) on other. There were also statistically significant positive correlations between extraversion and self-confidence (r = 0,39, p <0,01), consistency (r = 0,62, p <0,01), control (r = 0,30, p <0,01) and total mental toughness (r = 0,44, p <0,01). Statistically significant positive correlations were also found between conscientiousness and self-confidence (r = 0,30, p <0,01), consistency (r = 0,58, p <0,01), control (r = 0,23, p < 0,01) and total mental toughness (r = 0,52, p <0,01). Statistically significant negative correlations were found between emotionality on one hand and self-confidence (r= -0,37, p<0,01), consistency (r= -0,46, p<0,01), control (r= -0,46, p<0,01) and overall mental strength (r= -0,54, p<0,01) on the other. While correlations of agreeableness and openness to experience on one side and self-confidence, consistency, control, and overall mental toughness on the other were not statistically significant. Multiple regression analysis was performed with the aim of predicting the mental toughness of athletes based on their personality traits. Of the total variability of mental toughness, 34% of variability can be explained based on personality traits of athletes. The results showed that statistically significant predictor of mental toughness was emotionality. Partial contributions of other personality traits were not statistically significant. This study contributes to the understanding of which personality traits of athletes contribute to mental toughness, a coping mechanism when faced with challenges and reacting in competitive situations.

Indicator variables for inflation expectations in the euro area

In this paper, we model the Euro area market-based inflation expectations extracted from the inflation-linked swaps, and study the macroeconomic information embedded in expected inflation. First, we estimate the Gaussian affine term structure model to decompose the forward ILS-implied inflation rate into inflation expectations and inflation risk premium at one-, two- and three-year horizons. Secondly, from a large panel of macroeconomic series we identify the most significant indicator variables for inflation expectations using the elastic net modification of the LASSO regression. Finally, we measure partial contributions of individual indicator variables to the changes in inflation expectations. Our findings reveal that across horizons considered inflation expectations are correlated to the measures of current inflation of the overall price level and price level of services, the unemployment rate, and the Euro exchange rate. The identified indicators provide a useful information about the evolution of inflation expectations with different intensities at different horizons.

Distribution of alpha particle tracks on CR-39 detector in radon diffusion chamber

The aim of this study was to investigate spatial distribution of alpha particle tracks produced by radon and its progeny in radon diffusion chambers. Three cylindrical chambers equipped with CR-39 detectors were used in the experiment. Radon concentration was estimated using RAD7 device. Distribution of alpha particle tracks on detector surface was found to be nonuniform; track density close to the chamber walls was up to 30% lower than in the centre. The results were compared with the predictions of analytical method applied to the same chamber dimensions. Critical angle of detection was expressed in relation to particle incident energy, using TRACK_VISION computer software. It was shown that the shape of track density distribution highly depends on the chamber size, as well as on the critical angle of particle detection. Sources of track density variation were investigated by analyzing partial contributions from volumetric and deposited fractions of radon and its progeny. Side-wall contribution increases while volumetric and plateout contributions decrease with increasing radial distance from detector centre. Changing chamber dimensions affects the relative influences of these partial contributions, resulting in different distributions of visible tracks on detector surface. Experimental results were compared to the values obtained using previously developed software based on Monte Carlo method. Five different expressions of detector response function (V) were applied in the study; two of them significantly underestimated the experimental results.

Experimental and theoretical investigation of resonances in low-energy NO-H2 collisions.

The experimental characterization of scattering resonances in low energy collisions has proven to be a stringent test for quantum chemistry calculations. Previous measurements on the NO-H2 system at energies down to 10 cm-1 challenged the most sophisticated calculations of potential energy surfaces available. In this report, we continue these investigations by measuring the scattering behavior of the NO-H2 system in the previously unexplored 0.4 cm-1-10 cm-1 region for the parity changing de-excitation channel of NO. We study state-specific inelastic collisions with both para- and ortho-H2 in a crossed molecular beam experiment involving Stark deceleration and velocity map imaging. We are able to resolve resonance features in the measured integral and differential cross sections. Results are compared to predictions from two previously available potential energy surfaces, and we are able to clearly discriminate between the two potentials. We furthermore identify the partial wave contributions to these resonances and investigate the nature of the differences between collisions with para- and ortho-H2. Additionally, we tune the energy spreads in the experiment to our advantage to probe scattering behavior at energies beyond our mean experimental limit.

Graz Lagrangian Model (GRAL) for Pollutants Tracking and Estimating Sources Partial Contributions to Atmospheric Pollution in Highly Urbanized Areas

Computational modeling allows studying the air quality problems in depth and provides the best solution reducing the population risks. This research demonstrates the Graz Lagrangian model effectiveness for assessing emission sources contributions to the air pollution: particles tracking and accumulation estimate. The article describes model setting up parameters and datasets preparation for the analysis. The experiment simulated the dispersion from the main groups of emission sources for real weather conditions during 96 h of December 2018, when significant excess of NO2, CO, SO2, PM10, and benzo(a)pyrene concentrations were observed in the Krasnoyarsk surface atmospheric layer. The computational domain was a parallelepiped of 40 × 30 × 2.5 km, which was located deep inside the Eurasian continent on a heterogeneous landscape exaggerated by high-rise buildings, with various pollutions sources and the ice-free Yenisei River. The results demonstrated an excellent applicability of the Lagrange model for hourly tracking of particle trajectories, taking into account the urban landscape. For values <1 MPC (maximum permissible concentration) of peak pollutants concentrations, the coincidences were 93 cases, and for values < 0.1 shares of MPC, there were 36 cases out of the total number of 97. The same was found for the average daily concentration for values <1 MPC—31, and for values <0.1 MPC—5 matches out of 44. Wind speeds COR—65.3%, wind directions COR—68.6%. The Graz Lagrangian model showed the ability to simulate air quality problems in the Krasnoyarsk greater area conditions.

Style of faulting of expected earthquakes in Italy as an input for seismic hazard modeling

Abstract. The style of faulting and distributions of nodal planes are essential input for probabilistic seismic hazard assessment. As part of a recent elaboration of a new seismic hazard model for Italy, we defined criteria to parameterize the styles of faulting of expected earthquake ruptures and to evaluate their representativeness in an area-based seismicity model. Using available seismic moment tensors for relevant seismic events (Mw≥4.5), first arrival focal mechanisms for less recent earthquakes, and also geological data on past activated faults, we collected a database for the last ∼100 years by gathering a thousand data points for the Italian peninsula and regions around it. In this dataset, we adopted a procedure that consists, in each seismic zone, of separating the available seismic moment tensors into the three main tectonic styles, making a summation within each group, identifying possible nodal plane(s), taking into account the different percentages of styles of faulting, and including where necessary total or partial (even in terms of tectonic style) random source contributions. Referring to the area source model used, for several seismic zones we obtained robust results; e.g., along the central and southern Apennines we expect future earthquakes to be mostly extensional, although in the outer part of the chain reverse and strike-slip events are possible. In the northern part of the Apennines we expect different styles of faulting for different hypocentral depths. In zones characterized by a low seismic moment release, the possible style of faulting of future earthquakes is less clear and it has been represented using different combinations of random sources. The robustness of our results is confirmed when compared with recent relevant earthquakes occurring in Italy.

Age and mantle sources of Quaternary basalts associated with “leaky” transform faults of the migrating Anatolia-Arabia-Africa triple junction

Abstract The Anatolia (Eurasia), Arabia, and Africa tectonic plates intersect in southeast Turkey, near the Gulf of İskenderun, forming a tectonically active and unstable triple junction (the A3 triple junction). The plate boundaries are marked by broad zones of major, dominantly left-lateral transform faults including the East Anatolian fault zone (the Anatolia-Arabia boundary) and the Dead Sea fault zone (the Arabia-Africa boundary). Quaternary basalts occur locally within these “leaky” transform fault zones (similar to those observed within oceanic transform faults), providing evidence that mantle melting, basalt genesis, and eruption are linked to crustal deformation and faulting that extends into the upper mantle. We investigated samples of alkaline basalt (including basanite) from the Toprakkale and Karasu volcanic fields within a broad zone of transtension associated with these plate-boundary faults near the İskenderun and Amik Basins, respectively. Toprakkale basalts and basanites have 40Ar/39Ar plateau ages ranging from 810 ± 60 ka to 46 ± 13 ka, and Karasu volcanic field basalts have 40Ar/39Ar plateau ages ranging from 2.63 ± 0.17 Ma to 52 ± 16 ka. Two basanite samples within the Toprakkale volcanic field have isotopic characteristics of a depleted mantle source, with 87Sr/86Sr of 0.703070 and 0.703136, 143Nd/144Nd of 0.512931 and 0.512893, 176Hf/177Hf of 0.283019 and 0.282995, 206Pb/204Pb of 19.087 and 19.155, and 208Pb/204Pb of 38.861 and 38.915. The 176Hf/177Hf ratios of Toprakkale basalts (0.282966–0.283019) are more radiogenic than Karasu basalts (0.282837–0.282965), with some overlap in 143Nd/144Nd ratios (0.512781–0.512866 vs. 0.512648–0.512806). Toprakkale 206Pb/204Pb ratios (19.025 ± 0.001) exhibit less variation than that observed for Karasu basalts (18.800–19.324), and 208Pb/204Pb values for Toprakkale basalts (38.978–39.103) are slightly lower than values for Karasu basalts (39.100–39.219). Melting depths estimated for the basalts from both volcanic fields generally cluster between 60 and 70 km, whereas the basanites record melting depths of ∼90 km. Depth estimates for the basalts largely correspond to the base of a thin lithosphere (∼60 km) observed by seismic imaging. We interpret the combined radiogenic isotope data (Sr, Nd, Hf, Pb) from all alkaline basalts to reflect partial melting at the base of the lithospheric mantle. In contrast, seismic imaging indicates a much thicker (>100 km) lithosphere beneath southern Anatolia, a substantial part of which is likely subducted African lithosphere. This thicker lithosphere is adjacent to the surface locations of the basanites. Thus, the greater melting depths inferred for the basanites may include partial melt contributions either from the lithospheric mantle of the attached and subducting African (Cyprean) slab, or from partial melting of detached blocks that foundered due to convective removal of the Anatolian lithosphere and that subsequently melted at ∼90 km depth within the asthenosphere. The Quaternary basalts studied here are restricted to a broad zone of transtension formed in response to the development of the A3 triple junction, with an earliest erupted age of 2.63 Ma. This indicates that the triple junction was well established by this time. While the current position of the A3 triple junction is near the Amik Basin, faults and topographic expressions indicate that inception of the triple junction began as early as 5 Ma in a position farther to the northeast of the erupted basalts. Therefore, the position of the A3 triple junction appears to have migrated to the southwest since the beginning of the Pliocene as the Anatolia-Africa plate boundary has adjusted to extrusion (tectonic escape) of the Anatolia plate. Establishment of the triple junction over the past 5 m.y. was synchronous with rollback of the African slab beneath Anatolia and associated trench retreat, consistent with Pliocene uplift in Cyprus and with the current positions of plate boundaries. The A3 triple junction is considered to be unstable and likely to continue migrating to the southwest for the foreseeable geologic future.

The confined Be atom by soft potentials of Gaussian type

A study of the ground state of the confined beryllium atom under penetrable spherical walls of Gaussian type is carried out. The behavior of the total energy and its partial contributions: kinetic, electron–nucleus and electron–electron energies are analyzed as a function of the position of the barrier. A study about the behavior of the single particle energies and density is also performed. The Numerical Parameterized Optimized Effective Potential method is employed for all the calculations.

Partial contributions and temporal trends of leading causes of death during the last four decades in Spain

ObjectivesThe study was conducted to assess time trend shifts of leading causes of death and their partial contributions over the years 1975–2016 in Spain. Study designA longitudinal ecological epidemiologic design was conducted to analyse linear trend period shifts using joinpoint regression as the annual percentage of change (APC) in the period 1975–2016. The partial contributions were illustrated as the rate ratio of a singular-cause to their major-cause shift periods. ResultsHIV/AIDS shaped the increasing trend period of infectious diseases in 1989–1995 (APC = 25.3, P < 0.05) and the decreasing trend in 1995–1999 and 1999–2016. Lung cancer fell gradually from 1994 in men (−0.4, P < 0.05); however, in women, the condition continued increasing from 1990 (P < 0.05). Dementia types influenced mental and neurological disease drifts. The recent trend for circulatory periods (1980–2016) was mainly modulated by cardiac ischaemia, with increased partial contributions (25%, 32% and 30%). Traffic accidents defined the descending tendency of external causes. ConclusionsSpain showed a Western pattern in descended rates, including non-decreasing trends in mental and neurological diseases, pancreatic cancer, drug abuse and suicide. Trend shifts and partial contributions illustrated targets for further mortality reduction.

Photoproduction of K +Λ, and K +Σ0 on the proton

I analyze a possibility of building an isobar model of the kaon–hyperon pair photoproduction in the γp → K +Λ, , and γp → K +Σ processes, where the Born terms play a comparatively small role in the full amplitude. The total width of hadron resonances can be written in the form of a sum of partial contributions into the K +Λ, , and K +Σ channels, and the effective inelastic channel with zero strangeness. The introduction of the effective inelastic channel makes it possible to partially restore the broken unitarity of the total amplitude of photoproduction. The latter includes the gauge-invariant Born and resonant s-, t-, and u-channel contributions calculated in the tree-level approximation. The obtained sets of hadron decay widths of intermediate resonances and coupling constants calculated using these decay widths allow one to equally well reproduce the total and some differential cross sections of the K +Λ, , and K +Σ photoproduction.

Partial contributions to the valence band of MO2, RuO2, and Rh2O3: Cooper minimum and extended cluster model calculations

We studied the partial contributions to the valence band spectra of MoO2, RuO2 and Rh2O3. The experimental technique of choice was the Cooper minimum method to X-ray photoemission spectroscopy. The spectra were interpreted with an extended cluster model and compared to usual band structure calculations. We conclude that, for the correct description of the valence band, one must include charge transfer, final-state and many-body effects in the description of the electronic structure of these compounds, which can also be extended to other systems.

Properties of nuclear matter in relativistic Brueckner–Hartree–Fock model with high-precision charge-dependent potentials

Properties of nuclear matter are investigated in the framework of relativistic Brueckner–Hartree–Fock model with the latest high-precision charge-dependent Bonn (pvCD-Bonn) potentials, where the coupling between pion and nucleon is adopted as a pseudovector form. These realistic pvCD-Bonn potentials are renormalized to effective nucleon–nucleon (NN) interactions, G matrices. They are obtained by solving the Blankenbecler-Sugar (BbS) equation in nuclear medium. Then, the saturation properties of symmetric nuclear matter are calculated with pvCD-Bonn A, B, C potentials. The energies per nucleon are around −10.72 MeV to −16.83 MeV at saturation densities, 0.139 fm−3 to 0.192 fm−3 with these three potentials, respectively. It clearly demonstrates that the pseudovector coupling between pion and nucleon can generate reasonable saturation properties comparing with pseudoscalar coupling. Furthermore, these saturation properties have strong correlations with the tensor components of NN potentials, i.e., the D-state probabilities of deuteron, PD to form a relativistic Coester band. The equations of state of pure neutron matter from pvCD-Bonn potentials are almost identical, since the prominent difference of pvCD Bonn potentials are the components of tensor force, which provides very weak contributions in the case of total isospin T = 1. In addition, the charge symmetry breaking (CSB) and charge independence breaking (CIB) effects are also discussed in nuclear matter from the partial wave contributions with these high-precision charge-dependent potentials. In general, the magnitudes of CSB from the differences between nn and pp potentials are about 0.05 MeV, while those of CIB are around 0.35 MeV from the differences between np and pp potentials.

Embryonic cardioprotection by hydrogen sulphide: studies of isolated cardiac function and ischaemia-reperfusion injury in the chicken embryo.

In mammals, pregnancy complications can trigger an embryonic or fetal origin of cardiac dysfunction. However, underlying mechanisms remain uncertain because the partial contributions of the challenge on the mother, placenta or offspring are difficult to disentangle. The avian embryo permits isolation of the direct effects of suboptimal conditions during development on the cardiac function of the offspring, independent of additional effects on the mother and/or the placenta. Therefore, the objectives of this work were to adapt the isolated Langendorff technique using the chicken embryo to study the physiology of the developing heart. Here, we introduce a novel technique and show the utility of the technique for exploring cardioprotective roles of H2 S in the chicken embryo heart. This work lays the foundation for studying the direct effects of H2 S therapy on the embryonic heart independent of effects on the mother and the placenta in adverse development. This study adapted the isolated Langendorff preparation to study the chicken embryo heart in response to ischaemia-reperfusion (IR) injury. The utility of the technique was tested by investigating cardioprotective effects of hydrogen sulphide (H2 S) and underlying mechanisms. Embryonic hearts (19 out of 21 days of incubation) mounted on a Langendorff preparation were exposed to IR (30min ischaemia) after 4 treatments administered randomly, all as a 1mm bolus, into the perfusate: saline vehicle (control); sodium hydrogen sulphide (NaHS); NaHS plus glibenclamide, an antagonist of KATP opening (NaHS Glib), and Glib alone (Glib). Relative to controls, NaHS treatment improved cardiac function after ischaemia (mean±SD for area under the curve, AUC, for left ventricular developed pressure, LVDP: 1767.3±929.5 vs. 492.7±308.1; myocardial contractility, dP/dtmax : 2748.9±1514.9 vs. 763.7±433.1) and decreased infarct size (22.7±8.0 vs.43.9±4.2%) and cardiac damage (% change in creatinine kinase, 49.3±41.3 vs. 214.6±155.1; all P<0.05). Beneficial effects of NaHS were blocked by Glib. Glib alone had no effects. NaHS increased coronary flow rate (CFR) during baseline (mean±SD for AUC: 134.3±91.6 vs. 92.2±35.8) and post IR (1467±529.5 vs. 748.0±222.1; both P<0.05). However, this effect was not prevented by Glib. Therefore, the chicken embryo heart is amenable for study via the Langendorff preparation under basal conditions and during IR. The data show that H2 S confers embryonic cardiac protection via opening of myocardial KATP channels and not via increasing CFR. H2 S may prove a useful therapeutic agent to protect the human fetal heart against IR injury, as may occur in complicated labour.

Detection and localization of fatigue-induced transverse crack in a rotor shaft using principal component analysis

Rotor shafts subjected to severe operating stresses are prone to develop transverse fatigue cracks at the localized stress raisers. Therefore, the ability to identify and locate the incipient fatigue crack is imperative in order to avoid catastrophic failure. The literature on rotor crack detection discussed the importance of monitoring the steady-state 1X, 2X and 3X harmonic response components of rotors. However, the other rotor faults such as misalignment and unbalance, exhibit similar symptoms. Thus, the main aim is to develop new independent fault-related features which measure the driving principle governing the behaviour of various rotor faults. In this article, the application of principal component analysis–based statistical pattern analysis, as a tool for early detection and localization of fatigue-induced transverse crack in a rotor shaft is investigated. To perform this study, accelerated fatigue experiments are conducted on a customized setup. This developed test rig is novel and unique by itself that facilitates generating a fatigue crack in a shaft, under conditions that mimic a real in-service loading environment of industrial rotors. Unlike conventional methods, noise in the acquired vibration and strain data is denoised via classical principal component analysis method. Time- and frequency-domain statistical features extracted from different vibration and strain sensor signals are used for this study. Damage indices such as Hotelling’s T2-statistic and Q-index are used to detect the presence of the crack. It is observed that irrespective of the sensor location, damage index such as Q-statistic of all the sensors is very effective to detect the presence and time of incipient crack. Partial decomposition contributions method is found to be very effective in identifying the location of the crack. This article provides the most significant vibration-based statistical features, which are sensitive to shaft transverse cracks, for different sensor types and their mounting location. Finally, a new fused health indicator which is highly sensitive to the presence of rotor shaft crack is defined and is found successful when applied to a new experimental data.

Exploring the impact of central core modifications among several push-pull configurations to enhance nonlinear optical response

The present study explores a series of novel donor-π-acceptor (D-π-A) molecules containing 4,4′-dimethyldiphenylamine moiety as donor, 4,4′-dinitrodiphenylborane as acceptor while different π-bridges as efficient linkers between them, which comprises of (−HCCH−)n, (−Ph−)n and (−Ph ̶ HCCH−)n combinations for compounds in series 1, 2 and 3, respectively. Quantum chemical computations are applied to calculate the linear polarizability (α), first (β) and second (γ) hyperpolarizabilities. A comparative analysis is performed considering an increase of NLO polarizabilities as a function of different π-linkers. Among the investigated compounds, 3c shows the largest first and second hyperpolarizabilities of 1378 × 10−30 and 34971 × 10−36 esu, respectively. Interestingly, an increase in NLO polarizability is observed by modifying the π-conjugated bridges and the largest NLO polarizability is observed for series 3 possessing (Ph ̶ HCCH−)n π-linker which is found due to its lower transition energy and higher oscillator strengths. Furthermore, TD-DFT investigations, frontier molecular orbitals (FMOs) and electron density difference (EDD) maps analysis have shown a more efficient intramolecular charge transfer character from donor to acceptor moieties through (Ph ̶ HCCH−)n π-linkers. The density of states (DOS) maps are showing explicit contributions of electronic states from different fragments of a molecular system where the partial contributions of (Ph ̶ HCCH−)n π-linkers is seen significant in HOMO-LUMO orbitals of all the systems in series number 3. Thus, we believe that our study will highlight the importance of different D-π-A chromophores having variant types of π-conjugation cores as discussed in the present investigation.