Large NLO Research Articles

Exploring the influence of fused heterocyclic donor moieties on optical nonlinearity of styrylthiophene based chromophores: A DFT study

A new series of styrylthiophene based NLO compounds was designed with D-π-A configuration for NLO materials. The DFT calculations of designed derivatives (CTMFD1–CTMFD6) were performed at M06/6-311G (d,p) functional. A reduction in band gap with bathochromic shift (λmax = 644.107–712.430 nm) was seen in all designed derivatives as compared to reference chromophore (ΔE = 2.458 and λmax = 586.907 nm) except for CTMFD1. In FMO analysis, energy band gaps of designed derivatives were found to be smaller (1.901–2.319, eV) except CTMFD1 (2.824 eV) comparative to CTMFR (2.458 eV). Among all other molecules, CTMFD1 and CTMFD2 compounds showed the higher βtot of 5.370 × 10–27 and 4.837 × 10–27esu, while CTMFD4 compound showed the lowest value at 1.629 × 10–27esu. In the case of second hyperpolarizability (γtot), comparing with other derivatives, the larger value of γtot has also been found in the CTMFD2 compound which is 4.514 × 10–33esu, suggesting potential prospects for the advancement of large NLO scaffolds.

Four-jet event shapes in hadronic Higgs decays

We present next-to-leading order perturbative QCD predictions for four-jet-like event-shape observables in hadronic Higgs decays. To this end, we take into account two Higgs-decay categories: involving either the Yukawa-induced decay to a \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{b}}\\overline{{\ ext{b}} }$$\\end{document} pair or the loop-induced decay to two gluons via an effective Higgs-gluon-gluon coupling. We present results for distributions related to the event-shape variables thrust minor, light-hemisphere mass, narrow jet broadening, D-parameter, and Durham four-to-three-jet transition variable. For each of these observables we study the impact of higher-order corrections and compare their size and shape in the two Higgs-decay categories. We find large NLO corrections with a visible shape difference between the two decay modes, leading to a significant shift of the peak in distributions related to the H → gg decay mode.

Superalkali-alkaline earthide ion pairs of δ+(AM-HMHC)-AM'δ- (AM = Li, Na and K; AM' = Be, Mg and Ca) possessing large NLO responses and excellent electronic stabilities and alkalide characteristics: a DFT study.

To identify superalkali-alkaline earthide ion pairs, it's theoretically shown that, as a novel class of excess electron superalkali compounds, both chair and boat forms of (AM-HMHC)-AM' (AM = Li, Na, and K; AM' = Be, Mg, and Ca; HMHC = 1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacyclooctadecane) are good candidates. An attractive superalkali-alkaline earthide ion pair in δ+(AM-HMHC)-AM'δ- is firstly exhibited, which possesses alkaline-earthide characteristics and nonlinear optical response superior to similar M+(calix[4]pyrrole)M'- (M = Li, Na, and K; M' = Be, Mg, and Ca) with high stability. The electronic and vibrational second order hyperpolarizabilities and the frequency-dependent first hyperpolarizabilities of δ+(AM-HMHC)-AM'δ- are presented. For each pair of (AM-HMHC)-AM', the boat conformation is preferred to its chair one in the case of Hyper-Rayleigh scattering response (βHRS). These alkaline earthides suggest prominently high βHRS up to 2.59 × 104 a.u. (boat forms of δ+(Na-HMHC)-Caδ-). We expect that this work will inspire the preparation and characterization of these new alkaline earthides as high-performance NLO materials.

The switchable chirality and optical properties of hexabenzo[a,c,k,m,u,w]trinaphthylene controlled by synergistic effect of static electric field and substituents: A DFT study

This work selected the planar molecule hexabenzo [a,c,k,m,u,w]trinaphthylene (HBTN) with electron donor and acceptor, and introduced static electric field perpendicular to the conjugation plane for its control over molecular physical properties. With the guidance of electron donor and acceptor, controllable chirality, charge polarization, obvious charge transfer transition, Cotton effect and large NLO coefficients of molecule were obtained. The necessity of substituents to realize the control of static electric field to molecular chirality and optical properties was further confirmed by their locations and species. The direction of static electric field was also tested, and the importance of perpendicular field component was stressed. At last, the conclusion obtained via the discussion of monomer could also be applied to both homodimer and heterodimer, where same or different fragments were stacked via π-π interaction respectively. Especially for heterodimer, the completely different optical properties such as UV–Vis absorption spectra, ECD spectra and NLO coefficients between P- and M-type conformations were observed, and made it easier to recognize the chirality of heterodimer. All above results were meaningful to promote the application of molecules as chiral photovoltaic devices.

Phase Competition and Strong SHG Responses of the Li2MIIMIVSe4 Family: Atom Response Theory Predictions versus Experimental Results

Compounds of diamond-like (DL) structures are one of the important systems in searching for new high-performance infrared nonlinear optical (IR NLO) materials. However, the phase competition of the diverse DL allotropes and the origin of the SHG response at the atom and orbital level for these NLO materials remain an unsolved hot topic. In this work, the atom response theory (ART) combined with the hybrid density functional calculations was applied to explore the NLO properties of the Li2MIIMIVSe4 (MII = Zn, Cd, Hg; MIV = Si, Ge, Sn) family. Twenty-three new promising IR NLO compounds were predicted with a wide range of band gaps (1.79–3.62 eV), high SHG responses (∼0.7 to 2.5 × AGS), moderate birefringences (∼0.04), and possibly high LIDT (laser-induced damage threshold) values. Among them, Li2HgGeSe4 and Li2HgSnSe4 with the Pna21 structure were experimentally confirmed very recently. The phase competition and the order of band gaps of these compounds were explained from the viewpoint of the crystal structure and chemical bonding. Our ART analyses showed that the large NLO coefficients of these selenides arise mainly from the Se-4p orbitals (∼76%) while the anomaly low contribution of Hg is attributed to the tiny d–p covalent interactions. The SHG responses of all structures were rationalized by the deffp vs αsum/(NEg) linear relationship, showing the importance of this relation in designing and synthesizing new NLO materials.

A promising ultraviolet nonlinear optical crystal: Rb3Ba3Li2Al4B6O20F—crystal growth, physical properties, and 266 nm laser generation

The Rb3Ba3Li2Al4B6O20F crystal is a competitive ultraviolet NLO crystal, which not only can output 266 nm laser but also exhibits excellent comprehensive performances, such as large NLO coefficient, small walk-off and large acceptance angles.

Cyano-rich donor-acceptor-donor-type NLOphores containing dialkylated triazene and aniline groups

Continuous progress on the synthesis of push-pull chromophores is related to their outstanding optoelectronic properties. Expanding scope is a challenge due to the instability of targets and long synthetic strategies. Herein, we report the synthesis of thirteen different triazene-substituted alkyne substrates using Sonogashira cross-coupling reactions. Although we have previously described successful syntheses of homoconjugated and π-conjugated push-pull systems starting from triazene-substituted terminal alkynes, symmetric and unsymmetric bis-triazenes that we reported in this study unexpectedly did not undergo [2 + 2] cycloaddition-retroelectrocyclizations (CA-RE) with well-known electron acceptors, TCNE and TCNQ. With the use of diethylaniline-substituted substrates in CA-RE, this issue was successfully circumvented. Two different groups of NLOphores were synthesized in very high yields via [2 + 2] CA-RE with TCNE (95–99%) and TCNQ (92–99%). All target NLOphores were investigated by UV/Vis spectroscopy, thermal gravimetric analysis, high-resolution mass spectrometry, theoretical studies, and EFISHG experiments. While different dialkyltriazene groups did not appear to have an important impact on ICT properties of the chromophores, modifications made in the electron withdrawing units significantly affected the ICT performance of the chromophores. Target push–pull-systems displayed λmax values for their CT bands ranging between 454 and 692 nm. The ICT properties of the chromophores were confirmed by computational studies (Time-dependent density functional theory (TD-DFT) studies, frontier orbital visualizations, electrostatic potential maps, and calculation of several parameters such as dipole moment, HOMO-LUMO gaps, electronegativity, global chemical hardness, and softness, average polarizability, first hyperpolarizability) as well as experimental UV/Vis studies. As computational studies indicate that synthesized chromophores are potential NLOphores, experimental NLO measurements were performed by the EFISHG technique. Target structures exhibited large NLO responses (μβ values ranging 850 × 10−48 esu to 6050 × 10−48 esu).

Luminescent 1,10-Phenanthroline β-Diketonate Europium Complexes with Large Second-Order Nonlinear Optical Properties.

Substitution of the diglyme ligand of [Eu(hfa)3(diglyme)] (where hfa is hexafluoroacetylacetonate) with a simple 1,10-phenanthroline leads to a six-fold increase of the product μβEFISH, as measured by the Electric-Field-Induced Second Harmonic generation (EFISH) technique. Similarly, [Eu(tta)3(1,10-phenanthroline)] (where Htta is 2-thenoyltrifluoroacetone) is characterized by a large second-order NLO response. Both 1,10-phenanthroline europium complexes have great potential as multifunctional materials for photonics.

Assessment of alkali and alkaline earth metals doped cubanes as high-performance nonlinear optical materials by first-principles study

Novel organic materials have played a tremendous role in developing high-performance nonlinear optical materials. Herein, the geometric, electronic and nonlinear optical properties of designed alkali (Li, Na, and K) and alkaline earth metals (Be, Mg, and Ca) doped cubane (C 8 H 8 ) complexes have been explored by using density functional theory. Excess electrons generated by doping alkali/alkaline earth metals have significantly enhanced the NLO properties by reducing the crucial excitation energy of the cubane. The HOMO–LUMO energy gap of doped complexes is reduced up to 4.43 eV. It is revealed that the reduction in the HOMO–LUMO energy gap results from the development of the new highest occupied molecular orbital, which is confirmed by the density of state (DOS) analysis. The NBO analysis is carried out to confirm the charge transfer between metal atoms and the cubane ring. Further, the NCI and QTAIM analyses confirmed the nature of intramolecular interaction. The remarkable first hyperpolarizability ( β o ) of 3.01 × 10 4 au is observed for K@Cubane. Moreover, frequency dependent first hyperpolarizability ( β ( ω )), second harmonic generation β (-2 ω ; ω , ω ), electro-optic Pockel's effect β (- ω ; ω ,0), hyper-Rayleigh scattering coefficient ( β HRS ), second hyperpolarizability ( γ ( ω )), electric field-induced second harmonic generation γ (-2 ω ; ω , ω ,0) electro-optic Kerr effect γ (- ω ; ω ,0,0), and nonlinear refractive indices ( n 2 ) were also studied. The highest dc-Kerr (2.69 × 10 10 au ) and EFISHG (3.69 × 10 9 au ) values observed for K@Cubane along with large n 2 (1.73 × 10 −9 au ) justify the large NLO response. These intriguing outcomes will be advantageous for promoting the possible utilization of designed complexes in the field of high-performance NLO materials. • Alkali and alkaline earth metals doped cubane complexes have been investigated theoretically for better NLO response. • NBO analysis indicates the intermolecular charge transfer while NCI and QTAIM analyses validate non-covalent interactions. • All the doped complexes have deep ultraviolet transparency (≤200 nm). • First hyperpolarizability ( β o ) of doped cubane complexes have been enhanced to 3.01 × 10 4 au. • Hyper-Rayleigh scattering (upto 2.23×10 4 au ) and nonlinear refractive index (upto 1.15×10 −5 au ) reflect high NLO response.

Crystal growth and physicochemical characterization of urea doped 4-methoxyaniline (U-4MOA) single crystals for NLO and antimicrobial applications

The single crystals of 4-methoxyaniline doped with urea (U-4MOA) were grown by slow evaporation method. The crystal structure of the U-4MOA was determined to be orthorombic using single-crystal X-ray diffraction (SXRD) investigation. The existence of functional groups was substantiated by FT-IR spectrum. The percentage of elements contained in the grown crystal was estimated using EDAX analysis. The surface studies by scanning electron microscopy reveals the formation of interlaced pattern in U-4MOA crystal. Thermal properties of U-4MOA were determined by TGA and DTA methods and it melts at 69°C. The UV-visible study discloses the transparency of the grown crystal throughout visible region. Fluorescence spectrum of U-4MOA shows an emission band at 663 nm. The mechanical properties of U-4MOA were determined from Vickers's hardness testing. The electrical properties of the U-4MOA crystal were investigated using impedance analysis. SHG efficiency of U-4MOA was spotted to be 1.71 times greater than KDP. Z-scan analysis revealed that U-4MOA has a large third order NLO susceptibility. The antimicrobial activity of the grown U-4MOA sample was performed against certain pathogens for medicament applications. In addition, the crystal packing and intermolecular interconnection were determined using Hirshfeld surface analysis.

Exploration of nonlinear optical enhancement and interesting optical behavior with pyrene moiety as the conjugated donor and efficient modification in acceptor moieties

Herein, a series of new pyrene based hexylcyanoacetate derivatives (HPPC1–HPPC8) with A–π–D–π–D configuration were designed by end-capped modeling of non-fullerene acceptors on the structure of reference compound named dihexyl 3,3'-(pyrene-1,6-diylbis(4,1-phenylene))(2E,2'E)-bis(2-cyanoacrylate) HPPCR. Quantum chemical calculations of HPPCR and HPPC1–HPPC8 were accomplished at M06/6-31G(d, p) level. The stability of molecules due to the strongest hyper conjugative interactions in HPPCR and HPPC1–HPPC8 was estimated through NBO study. Interestingly, HOMO–LUMO band-gap of HPPC1–HPPC8 was found smaller than HPPCR which resulted in large NLO response. Among all the investigated compounds, HPPC7 showed the larger NLO response due to the presence of four cyanide (CN) groups which strengthens the bridge conjugation, and its band gap was found to be 2.11 eV, smaller as compared to band gap of HPPCR (3.225 eV). The absorption spectra of HPPC1–HPPC8 compounds showed maximum absorption wavelengths (483–707 nm) than HPPCR (471.764 nm). The designed compounds showed high NLO response than HPPCR. Amazingly, highest amplitude of linear polarizability < α > , first hyperpolarizability (βtotal) and second hyperpolarizability < γ > for HPPC7 were achieved to be 1331.191, 200,112.2 and 4.131 × 107 (a.u), respectively. NLO response showed that the HPPC1–HPPC8 might be potential candidates for NLO applications.Graphical abstract

Superalkali (Li2F, Li3F) doped Al12N12 electrides with enhanced static, dynamic nonlinear optical responses and refractive indices

In the present work, superalkalis (Li2F and Li3F) doped Al12N12 nanocages have been designed and investigated theoretically to elucidate the correlations between geometric, electronic and nonlinear optical properties. All complexes (A-E) are stable inorganic electrides as indicated by their interaction energies (−52.97 to −87.58 kcal/mol). The decrease in HOMO-LUMO energy gaps (5.44–5.87 eV) has caused a remarkable increase in the nonlinear optical response of A-E complexes. The maximum values of first hyperpolarizability (1.20 × 104 a.u.) and second hyperpolarizability (1.65 × 107 a.u.) have been achieved for complex A. The highest dynamic hyperpolarizability coefficients including second harmonic generation (9.08 × 105 a.u.) and electro-optic Pockel's effect (9.56 × 105 a.u.) are obtained for complex A at 532 nm. The electric field-induced second harmonic generation (up to 3.52 × 108 a.u.) and dc-Kerr effect (up to 8.13 ×108 a.u.) along with a large quadratic nonlinear refractive index (up to 5.41 × 10−11 a.u.) of the designed electrides reflected their large NLO response.

Pnictides: An emerging class of infrared nonlinear optical material candidates

New infrared nonlinear optical (IR NLO) crystals with strong NLO efficiency, high laser damage threshold, excellent phase-matching ability and good IR transmittance, are urgently desirable because the commercial IR NLO materials (e.g., AgGaS2, AgGaSe2, and ZnGeP2) with inevitable defects are limited for high power laser applications. Pnictides are highly promising IR NLO candidate materials due to their probably large second-order NLO coefficient. After years of silence, the exploration on pnictide NLO crystals has emerged bring out numbers of excellent IR NLO pnictides. This review summarizes the achievements on IR NLO pnictides by focusing on their crystal structures and several key NLO indexes, and then get deep insight into their structure-property correlations. Furthermore, the existing issues and prospective development of NLO pnictides are also proposed and discussed.

Comprehensive study of -Alanine passivated colloidal gold nanoparticles and GNP-PVP thin films: Linear optical properties and very large nonlinear refractive index, absorption coefficient, third-order nonlinear susceptibility measurements and effect of passivation

We synthesized gold nanoparticles (GNPs) stabilized in various concentration of l-alanine by chemical reduction method. We measured NLO responses of GNPs when they are dispersed in the l-alanine stabilizer with 1, 2.5 and 5 mM concentrations and when they are implanted into the PVP matix, by using single beam Z- Scan technique with 632 nm He–Ne CW laser for excitation. GNPs exhibited blue shift in localised surface plasmon resonance (LSPR) peak with the l-alanine concentration. The fcc structured GNPs of reducing size with the stabilizer concentration were obtained and characterized by the TEM as well as XRD. The FTIR spectral investigation revealed the formation of strong bond between the surface of GNPs and the l-alanine functional groups and established that l-alanine is very good candidate for stabilization of MNPs. It was observed that these samples show very large nonlinear refractive index, absorption coefficient and third-order nonlinear susceptibility in the order of 10−8cm2W−1, 10−6 cmW−1 and 10−9esu respectively for colloidal suspension of GNPs, and for the GNP-PVP thin films these parameter values were found in the order of 10−6cm2W−1, 10−5cmW−1and 10−6esu respectively. The thermally stimulated, l-alanine concentration dependant, very large NLO responses attributed to the local field effect from Mie resonance and thermal lensing effect originated from thermo-optic phenomenon. The obtained results validate the influence of the stabilizer (l-alanine) on NLO properties.

Single production of vector-like quarks: the effects of large width, interference and NLO corrections

We provide a comprehensive discussion, together with a complete setup for simulations, relevant for the production of a single vector-like quark at hadron colliders. Our predictions include finite width effects, signal-background interference effects and next-to-leading order QCD corrections. We explicitly apply the framework to study the single production of a vector-like quark T with charge 2/3, but the same procedure can be used to analyse the single production of vector-like quarks with charge −4/3, −1/3, 2/3 and 5/3, when the vector-like quark interacts with the Standard Model quarks and electroweak bosons. Moreover, this procedure can be straightforwardly extended to include additional interactions with exotic particles. We provide quantitative results for representative benchmark scenarios characterised by the T mass and width, and we determine the role of the interference terms for a range of masses and widths of phenomenological significance. We additionally describe in detail, both analytically and numerically, a striking feature in the invariant mass distribution appearing only in the T → th channel.

Investigation on the growth, optical, electrical, thermal and third order NLO properties of 2-(4-methlybenzylidene) malononitrile (MBM) single crystal

More effective organic charge transfer nonlinear optical material of 2-(4-methlybenzylidene) malononitrile (MBM) has been synthesized via knoevenagel condensation reaction method and single crystals of unprecedented MBM were successfully cultivated in the presence of ethanol solution by the adaption of slow evaporation solution growth method. Cell parameters and phase purity of the obtained MBM crystals were investigated with the help of Single crystal and powder X-ray diffraction analysis. The morphology of the grown crystal was generated using WinXMorph software. Linear optical characterization was carried out in order to figure out its transmittance efficiency (82%), cut-off wavelength (λ = 458 nm) and energy band gap (Eg = 3.05eV) of the title material. Electrical behavior of the MBM crystal was examined on the basis of dielectric properties. Title crystals thermal tolerance and melting point was examined through TG-DSC analysis. The grown MBM crystal was subjected to Single beam Z-scan technique in order to figure out its third order nonlinear optical nature and its susceptibility is compared with other reported centrosymmetric crystals. Considering its large transmittance range, thermal stability and effective NLO performance, MBM is a potential candidate for NLO applications.

Anti-inflammatory (AI) and crystalline hardness characterisations of 4-(4-chlorophenyl)-7,7-dimethyl-7,8-dihydro-4h-1-benzopyran-2,5(3h,6h)-dione-(CPDMDHHBPHHD) – Comparative analysis of macro and nano scales crystals

CPDMDHHBPHHD nano crystals are having colossal opto-electronic application, stage coordinating, recurrence coordinating and power transmission and different utilities. Full scale crystals have least applications by esteem contrasted with nano type of CPDMDHHBPHHD arranged by processing strategy. The nano type of CPDMDHHBPHHD crystals are of 228 nm, to 16 nm individually, the XRD information uncovers the full scale crystals are having the equation C17H17ClO3 are of a = 11.9005 Å, b = 5.7971 Å, c = 22.608 Å, β = 93.97°, monoclinic with space group P21/n, the large scale level NLO is 1.25 occasions than that of standard KDP. Here both the large scale and nano precious stones are experienced with anti-inflammatory activity and nano structure very appropriate for medicate dependent on the qualities. Large scale crystals with anti-inflammatory activity have hardness concentrates as well and brought about hard class of materials. The sample is having Anti diabetic character also and good in electronic filter utilities too for the societal utility by electronic and by bio and pharma applications.

Superhalogen doping: a new and effective approach to design materials with excellent static and dynamic NLO responses

The first-ever example where superhalogen doping alone is introduced as a new and effective approach to impart large NLO responses.

NLO QCD predictions for t overline{t} b overline{b} production in association with a light jet at the LHC

Theoretical predictions for t overline{t} b overline{b} production are of crucial importance for t overline{t} H measurements in the H → b overline{b} channel at the LHC. To address the large uncertainties associated with the modelling of extra QCD radiation in t overline{t} b overline{b} events, in this paper we present a calculation of pp → t overline{t} b overline{b} j at NLO QCD. The behaviour of NLO corrections is analysed in a variety of observables, and to assess theoretical uncertainties we use factor- two rescalings as well as different dynamic scales. In this context, we propose a systematic alignment of dynamic scales that makes it possible to disentangle normalisation and shape uncertainties in a transparent way. Scale uncertainties at NLO are typically at the level of 20–30% in integrated cross sections, and below 10% for the shapes of distributions. The kinematics of QCD radiation is investigated in detail, including the effects of its recoil on the objects of the t overline{t} b overline{b} system. In particular, we discuss various azimuthal correlations that allow one to characterise the QCD recoil pattern in a precise and transparent way. In general, the calculation at hand provides a variety of precise benchmarks that can be used to validate the modelling of QCD radiation in t overline{t} b overline{b} generators. Moreover, as we will argue, pp → t overline{t} b overline{b} j at NLO entails information that can be used to gain insights into the perturbative convergence of the inclusive t overline{t} b overline{b} cross section beyond NLO. Based on this idea, we address the issue of the large NLO K-factor observed in {sigma}_{toverline{t}boverline{b}} , and we provide evidence that supports the reduction of this K-factor through a mild adjustment of the QCD scales that are conventionally used for this process. The presented 2 → 5 NLO calculations have been carried out using OpenLoops 2 in combination with Sherpa and Munich.

Ba10In6Zn7S26- nZnS: An Inorganic Composite System with Interface Phase-Matching Tuned for High-Performance Infrared Nonlinear Optical Materials.

Mid- and far-infrared nonlinear optical (MFIR NLO) materials are important in modern laser technologies. However, it is very challenging to develop materials that can achieve a subtle balance between the key requirements, such as large NLO response, high laser-induced damage threshold (LIDT), wide IR transparency, and phase-matching. In this work, a new wide IR transparency (0.38-15.3 μm) NLO crystal Ba10In6Zn7S26 (SS26) is synthesized. Further, its composite system Ba10In6Zn7S26- nZnS is synthesized by eutectic reaction. In particular, Ba10In6Zn7S26-14ZnS (SS40) shows excellent balanced NLO performance that includes a large band gap of 3.05 eV, high LIDT (13.3 × AgGaS2), large second harmonic generation (SHG) response (2.1 × AgGaS2 at 2050 nm, 5.2 × KDP at 1064 nm), and wide optical transmission window (0.37-15.4 μm). Importantly, the phase-matching condition is realized for SS40 by interfaces formed between the crystal face (112) of matrix SS26 and the crystal face (111) of reinforcement cubic ZnS by topological chemical reaction, and the NLO performance can be tuned by different concentrations of ZnS. First-principles simulations are employed to study NLO properties of SS26 and the interfaces. This work demonstrates that SS40 is a promising MFIR NLO material, and tuning components of the composite material system is a useful way to develop new MFIR NLO materials with excellent comprehensive performance.