Hyperpolarizability Values Research Articles

Structural and spectroscopic characterization of the products formed in aqueous solution of hydrazine and maleic acid

• Structural and Spectroscopic studies were carried out using XRD and Spectroscopic techniques. • NBO and HOMO-LUMO energies were estimated. • DFT calculations were accomplished by using B3LYP with 6-311++G(d,p) basis set. • The intermolecular interaction has been evaluated by Hirshfeld surface analysis. The detailed investigation of the structural and spectroscopic characterization of the products formed in aqueous solution of hydrazine and maleic acid is studied in the current research. Single crystal X-ray diffraction inquiry concedes that obtained crystal hydrazinium fumarate ( 1 ) crystallises in the centrosymmetric space group P2 1 /c of the monoclinic system with four molecules per unit cell, whereas maleic hydrazide in the monolactim form ( 2 ) crystallises in the triclinic system with centrosymmetric space group and possess two molecules per unit cell. Further the structure of hydrazinium fumarate is optimized by using density functional theory with B3LYP/6-311++G(d,p) level. Structural and vibrational spectral analysis has been established by both experimental and theoretical method. B3LYP exchange correlational hybrid with 6-311++G (d, p) basis sets are used to assign all modes of vibration and analyse the structure of the molecule in terms of parameters like bond length, bond angle, and dihedral angle. The charge transfer between localised bonds and lone pairs is visualised via NBO analysis. The HOMO–LUMO mappings are presented, revealing the molecule's many charge transfer possibilities. The non-linear attribute of the molecule is described using the dipole moment (μ), polarizability (α), and hyperpolarizability (β) values of the molecule. The Crystal Explorer Ver. 3.1 tool is used to calculate Hirshfeld surface analyses, 2D fingerprint plots, and percentage contributions for several intermolecular interactions in the examined crystal hydrazinium fumarate (1).

Theoretical Investigation of 1H and 13C NMR Spectra of Diethanol Amine Dithiocarbamate RAFT Agent

In this study, quantum chemical studies of diethanolamine dithiocarbamate (DADC) RAFT compound were carried out. For this purpose, the composite was optimized by using the DFT / B3LYP method 6-311G and the B3PW91 method SDD basis set. By using the optimized structure obtained according to the GIAO method, 1H and 13C NMR chemical shift values in the gas phase were calculated. According to the results obtained, it was seen that the theoretical data were coherent with the experimental data. In addition, in the theoretical part of the study, the FT-IR frequency values of the compound synthesized by using the same methods and basic set were compared experimentally and theoretically. In addition, the structure details and analysis of molecules, electronic properties such as HOMO and LUMO energies, molecular electrostatic potential (MEP) and thermodynamic properties have been performed. The electric dipole moment (μ) and the initial hyperpolarizability (β) values of the studied molecule were calculated by using ab initio quantum mechanical calculations. In addition, the calculated results show that the (DADC) molecule can have nonlinear optical (NLO) behavior with nonzero values. Neutral Band Orbital (NBO) analysis has been calculated with DFT / B3PW91/SDD basis set.

Investigation of the structural, Hirshfeld surface, Z-scan, and molecular modelling of imidazolium fumarate for third harmonic generation applications

• IMFA was synthesized and characterized by various physicochemical studies. • FTIR analysis is done for both parent and product materials. • The first order hyperpolarizability value of IMFA is 2.68 × 10 −30 esu. • The grown crystal becomes transparent and the E g value is 4.15 eV. • The third order NLO properties have been calculated by using Z-scan studies. Single crystals of imidazolium fumarate (IMFA) have been grown and subjected to several experimental studies. Single crystal XRD studies affirm that the IMFA crystal system belongs to the triclinic with a centrosymmetric space group of P-1. The fundamental vibrational modes were affirmed by the FTIR studies. The FT-NMR spectrum was recorded to interpret the number of protons and carbons present in the grown crystal. The grown crystal has good transmission in the region of 400 to 1050 nm. The grown crystal 3 rd order NLO properties have been calculated by using Z-scan studies. The Hirshfeld surface and related fingerprint plots of the IMFA molecule have been analysed. The title molecule electrophilicity index and energy gap HOMO-LUMO were determined. Moreover, the DFT computation of the optimized geometries, NBO, MEP, and molecule hyperpolarizability calculations were also made to explore the structure-property relationship. Graphical Abstract. .

Density Functional Theory Study of the Structural, Electronic, Non-Linear Optical and Thermodynamic Properties of Poly (3-Hexylthiophene-2, 5 - Diyl) in Gas Phase and in Some Solvents

Poly(3-hexylthiophene-2,5-diyl) (P3HT) and its derivatives are polymer based materials with π conjugation framework. P3HT is useful photoelectric material and can be used in organic semiconductor devices such as PLED, OLED, Nonlinear optical devices and solar cells. In this work, a theoretical study of P3HT in the gas phase and in some solvents (methanol, thiophene, chloroform, toluene, and acetone) were investigated and reported based on Density Functional Theory (DFT) as implemented in Gaussian 09 package using B3LYP/6-31++G (d, p) basis set. Structural properties such as bond lengths and bond angles as well as the HUMO, LUMO, energy gap, global chemical index, thermodynamic properties, NLO and DOS of the P3HT molecule in order to determine the reactivity and stability of the molecule were obtained. The results obtained showed that the solvents have effects on the structural, electronic and non-linear-optical properties of the molecule. The optimized bond length revealed that the molecule has a stronger bond in methanol with smallest bond length of about 1.0840Å (C28-H35) than in gas phase and the rest of the solvents. It was observed that the molecule is more stable in methanol with HOMO-LUMO energy gap and chemical hardness of 3.8338eV and 1.9169eV respectively. This indicates that the energy gap and chemical hardness of P3HT molecule increase with the increase in polarity and dielectric constants of the solvents. The energy gap obtained is compared with the one in literature \((3.10 \mathrm{eV})\). This indicates that the reported energy-gap leads by about \(0.7 \mathrm{eV}\). The calculations of thermodynamic properties indicate that P3HT molecule has the highest value of specific heat capacity \((\mathrm{CV})\), that is \(152.307 \mathrm{Cv}(\mathrm{Kcal} / \mathrm{Mol})\) in methanol, toluene has the highest value of entropy as \(266.960\) (Kcal/Mol), and thiophene has the highest value of zero-point vibrational energy (ZPVE) as \(455.37486 \mathrm{Kcal} / \mathrm{Mol}\). The NLO properties show that methanol has the highest value of total dipole moment ( \(\mu_{\text {tat }}\) ) as \(1.01764\) a u while acetone has the highest value of first order hyperpolarizability ( ( tot) as \(4.4447 \times 10^{-30}\) esu than the rest of the solvents. The values obtained for the first order hyperpolarizability for P3HT in acetone is about 12 times than that of the urea molecule, \(\left(0.3728 \times 10^{-30} \mathrm{esu}\right)\) which is commonly used for the comparison of NLO properties The results of the \(I R\) spectra show that the studied molecule was stable in both the gas phase and in solvents since no imaginary frequency was observed. It was also observed that the most intense frequency was found to be \(3024.9421 \mathrm{~cm}^{-1}\) at an intensity of \(140.2464 \mathrm{~km} / \mathrm{mol}\) in methanol and \(3088.6908\) \(\mathrm{cm}^{-1} at intensity of 77.6119 \mathrm{~km} / \mathrm{mol}\) in gas phase. The theoretical values of the open circuit voltage were found to be \(1.635 \mathrm{eV}, 1.614 \mathrm{eV}, 1.605 \mathrm{eV}, 1.576 \mathrm{eV}, 1514 \mathrm{eV}\), and \(1.445 \mathrm{eV}\) for methanol, toluene, acetone, chloroform, thiophene and the gas phase respectively. These changes in the properties of the molecule are observed due to the differences in the dielectric constants of the solvents. The results show that careful selection of the solvents can enhance the properties of the molecule for Organic solar cells (OSC)s applications.

Connecting two intrinsic electron donor and acceptor moieties through distinctive π-bridging units to explore their optical and nonlinear optical properties

Boraphenalene and pyrido(2,1,6-de)quinolizine moieties are intrinsically electron acceptor and donor groups, owing to their electron deficient and electron rich characteristics, respectively. In the current study, quantum computations are executed for investigating the charge transfer character and nonlinear optical (NLO) response for various combinations of boraphenalene and pyrido(2,1,6-de)quinolizine derivatives. The effect of various π-conjugated connectors i.e. direct ring attachment (1AB), ethylene (2AB), acetylene (3AB) and phenylene (4AB) units on optical and NLO properties were studied. Density functional theory (DFT) techniques are employed for computing the responses properties for designed compounds (A, B, 1AB, 2AB, 3AB and 4AB). From the studied compounds, 4AB exhibits the leading average second-order NLO polarizability of 954.8 × 10-30 esu, which was about 148 times greater than para-Nitroaniline (p-NA) molecule (a typical push-pull NLO molecule). The source of greater values of hyperpolarizability is tracked through TD-DFT computations where electronic transitions having better oscillator strengths along with lower transition energies are seen more contributing in hyperpolarizability. Additionally, the assessment of electrostatic potentials (ESPs), density of states (DOS), frontier molecular orbitals (FMOs) and transition density matrix (TDM) diagrams provide a molecular-level insight into the structures and their relationship to NLO properties of designed derivatives. Hence, the current investigation would arouse the curiosity of other scientists in the field for such different and novel strategy for designing NLO materials.

Synthesis, crystal structure, Hirshfeld surface, nonlinear optical properties and computational studies of (E)-4-bromo-N'-(3,4-dimethoxybenzylidene)benzohydrazide single crystal for nonlinear optical applications

(E)-4-bromo-N'-(3,4-dimethoxybenzylidene)benzohydrazide (DMBH) single crystals were synthesized by Schiff base method. The crystal structure of DMBH single crystal was determined using single crystal X-ray diffraction technique. The proton 1H and carbon 13C NMR spectral analysis were studied to identify the molecular structure of the crystal. From UV–Vis spectral analysis the maximum absorption for the DMBH molecule was observed around 338 nm and it reveals the presence of π-π* transition. The different functional group properties were studied via Fourier transform infrared (FTIR) analysis. Density functional theory (DFT) method was used to investigate the HOMO and LUMO energies and their energies were interrelated with the UV spectral analysis. Inter and intra molecular interactions with the assistance of colour coding were discussed using Hirshfeld surface analysis. The intramolecular stabilization by donor-acceptor interactions was investigated with the aid of natural bond orbital (NBO) analysis. In addition, the reactivity of the title compound was calculated by molecular electrostatic potential (MEP) analysis. For DMBH crystal, the first order hyperpolarizability value β0 = 5.0786 × 10−30 esu was obtained and is around 14 times greater than that of urea (0.3728 × 10−30 esu). The third order nonlinear optical (NLO) properties were studied through Z-scan method.

DFT-based modeling of polypyrole/B12N12 nanocomposite for the photocatalytic applications

Boron-based nanocomposites considered as one of the most promising photocatalysts, have drawn significant attention in the degradation of pollutants in aquatic environments. In this regard, density functional theory calculations were carried out on the B12N12 nanocluster interacted with various lengths of (PPy)n oligomers (n = 3, 5, 7, and 9) to predict the optical, electronic, charge transfer properties as well as the optimum composition of obtained (PPy)n/B12N12 nanocomposites. It was found that the most stable nanocomposite corresponds to (PPy)3/B12N12, which was supported by its greatest adsorption energy (−59.460 kcal mol−1) in the gas phase. The calculations in the gas phase and water showed that water as a solvent has a key role in the interaction between B12N12 nanocluster and (PPy)n oligomers. The results revealed that the adsorption of (PPy)9 oligomer on the B12N12 nanocluster leads to the highest reduction (∼ 2.672 eV) in the energy gap (Eg) value, while the lowest reduction (∼ 1.475 eV) was related to (PPy)3/B12N12 nanocomposite. Moreover, the natural bond orbital analysis showed that the charge flows from (PPy)n oligomers to the B12N12 nanocluster. Polarizability (α0) and first hyperpolarizability (β0) values revealed that the adsorption of (PPy)9 oligomer on the surface of B12N12 nanocluster has the most considerable effect on the optical response of B12N12 nanocluster due to increasing the α0 and β0 values about 492.49 and 5070.07 a.u, respectively. The UV–Vis spectra analysis showed that the (PPy)9/B12N12 nanocomposite has the highest bathochromic shift (∼ 245.39 nm) among other nanocomposites. Finally, quantum theory of atoms in molecules analysis showed that (PPy)n oligomers interact with B12N12 nanocluster through the partial covalent interactions.

DFT quantum chemical calculations (Fukui functions, NLO, TDOS, OPDOS, DNA/ECT) on 4-(dec-2yn-1-yloxy)phthalonitrile

In this study, structural and electronic properties of 4-(dec-2yn-1-yloxy)phthalonitrile were analyzed theoretically. The optimized structure in the gas phase of the title compound was achieved by density functional theory (DFT) method with the B3LYP hybrid functional using 6-31G (d,p) basis set. Then, IR, 1H-NMR, 13C-NMR spectroscopic properties of the title molecule were calculated and compared with the corresponding experimentally ones. Besides these, the molecular electrostatic potential (MEP) surface, frontier molecular orbitals (FMO), chemical activity, Fukui function analysis, nonlinear optical properties (NLO) in different solvent environments, total (TDOS), partial (PDOS) and overlap population density of state (OPDOS) diagrams were offered. Finally, the interactions between the title molecule with adenine, cytosine, thymine and guanine which are DNA bases were investigated by using the electrophilicity-based charge transfer (ECT) method and charge transfer (ΔN). According to NLO calculations, the value of the first hyperpolarizability of the title compound in the gas phase was found nearly twenty two times more than that of urea.

Electronic, non-linear optical, optoelectronic, and thermodynamic properties of undoped and doped bis (ethylenedithio) tetraselenafulvalene (BETS) (C10H8S4Se4) molecule: first study using ab initio investigation.

We have performed the ab initio calculation of the undoped and doped molecules bis (ethylenedithio) tetraselenafulvalene (BETS). Carbone (C) atoms have been substituted by Boron (B) to investigate their effects on the electronic structure and nonlinear optical, optoelectronic, and thermodynamic properties of BETS molecule. The RHF and hybrid density functional theories (WB97XD, B3PW91, and B3LYP) methods were applied, using the cc-pVDZ basis set. We found that the energy gap (Egap) of the doped molecules are respectively 2.476eV and 2.569eV for C8B2H8S4Se4 and C7B3H8S4Se4 with B3LYP/cc-pVDZ basis set, lower than one of the undoped molecule (3.316eV). The significant increase values of polarizability (˂α˃) and first order hyperpolarizability (β) of the doped compounds, especially in C8B2H8S4Se4 (< α > = 4.5315 × 10-23 esu, β = 22,672.27 × 10-33 esu and < α > = 4.518 × 10-23 esu, β = 23,657.43 × 10-33 esu respectively for B3LYP and B3PW91) compared to those of the undoped molecule (< α > = 4.3602 × 10-23 esu, β = 1290.38 × 10-33 esu, and < α > = 4.518 × 10-23 esu) show that the new molecules have a good nonlinear optical property. Results suggest that these molecules doped with boron are a potential candidate as semiconductors compounds and nonlinear optical materials.

Efficient Synthesis of 4‐Bromo‐N‐(1‐phenylethyl)benzamide, Arylation by Pd(0) Catalyst, Characterization and DFT Study

AbstractThe (S)‐4‐bromo‐N‐(1‐phenylethyl)benzamide (3) was synthesized in excellent yield (93 %) by the reaction of 4‐bromobenzoic acid (1) and (S)‐1‐phenylethanamine (2) with the coupling reagent titanium tetrachloride (TiCl4). Further, the Pd(0) catalyst was employed to form (S)‐4‐bromo‐N‐(1‐phenylethyl)benzamide analogues (5 a‐i) by reacting various aryl boronic acids with 4‐bromo‐N‐(1‐phenylethyl)benzamide (3) in moderate to good yields (62‐89 %). Furthermore, DFT studies were carried out to compute optimized geometries, frontier molecular orbitals, polarizability (α), hyperpolarizability (β), MESP, reactivity descriptors, and NMR spectra. The measured NMR values matched the experimental NMR values well. In this series (5 a‐i), we predicted that the highest energy difference between the HOMO‐LUMO of compound (5 a) has 4.98 eV, resulting in a more stable compound, and compound (5 g) has the lowest energy difference between the HOMO‐LUMO 4.63 eV, resulting in the least stable compound. Compound (5h) has the highest hyperpolarizability (β) value, exhibits a better non‐linear optical (NLO) behaviour compared as compare to other synthesized compounds in the series.

Synthesis, characterization and theoretical studies of the photovoltaic properties of novel bifunctional reactive disperse dyes based on aminothiazole derivatives

This article comprises synthesis and characterization of two polyfunctional diazo reactive-disperse dyes with aminothiazole moiety for application in dye-sensitized solar cells (DSSC). The characterization techniques employed were Gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-vis), and Nuclear magnetic resonance (NMR) to determine the different functional groups, molecular connectivities and molecular weight of the various fragments of the synthesized dyes. Theoretical Density Functional Theory (DFT) and Time-Dependent TD-DFT calculations were performed using B3LYP/6-311+g(d,p). It can be observed that the HOMO energy levels of the respective dyes have lower values than I−/I3− redox couple level (around -4.80 eV) in the four different phases studied, which is crucial for the regeneration of the oxidized dye molecule and efficient charge separation. Furthermore, the HOMO-LUMO energy gaps of DYES F and S are within the range 2.38-5.40 eV, where all LUMO-CB of TiO2 energy gap values are sufficient for generating enough driving force for effective electron injection. The promising results of Light-harvesting efficiency (LHE) (values ranging from 0.81 to 0.89 except for DYE S in chloroform phase where it has an unusual value of 0.21) and Open-circuit voltage (VOC) values gotten compared with other organic, and natural sensitizers were due to the better interaction between the carboxyl and carbonyl groups of aryl azo molecule joined to the thiazolyl nucleus and the surface of TiO2 permeable film. DYE S exhibits the lowest band gap (2.374eV), which designates the highest chemical activity of the two dyes. Results from the quantum theory of atoms-in-molecules indicate that DYES F and S exhibit additional stability due to their relatively high H-bond interactions as well as certain additional intra-atomic bonds among the atoms of the investigated compounds. The outcome of the Natural bond orbital (NBO) analysis suggests that the strongest charge transfer occurs in DYE S as compared to DYE F. The types and modes of excitations for the first five excited states of the synthesized dyes were observed from the results of the hole-electron excitation analysis. First hyperpolarizability values of the dye F and dye S were determined to be 47.24 and 46.90 times the hyperpolarizability value of urea, demonstrating its excellent non-linear optical (NLO) response.

Exploration of Pull-Push Effect for Novel Photovoltaic Dyes with A-π-D Design: A DFT/TD-DFT Investigation.

The π-rich versus π-poor units in 4,6-di(thiophen-2-yl)pyrimidine (DTB) alternating the π-backbone of solar cells dyes have been extended with a push-pull technique to lower their HOMO-LUMO energy gap and to increase Intramolecular Charge Transfer (ICT). Density functional theory was used to optimize the ground state moleculargeometries of newly designed dyes (DTB1-DTB6). Time Dependent DFT (TD-DFT) was used to simulate the Uv-vis spectral values at the maximum absorbance values ranging between 481-535nm. These values were red shifted from DTB value of experimental (333nm) and theoretical (346nm). however, their computed absorbance and fluorescence spectra revealed a bathochromic shift of them upon an increasing the solvent polarity. Different DFT functionals such as (B3LYP, CAM-B3LYP, B97XD, and APFD) were employed to choose their proper use Uv-visible analysis to revealan unexpected coherence at the B3LYP level withexperimentalvalues. As a result, the B3LYP with most diffused basis sets of 6-31G + (d,p) were used for further calculations. The parameters of Global Chemical reactivities revealed that all the dyes had a softer nature with their softness value range of 0.27-0.41. their Ionization Potentials (IP) ranged between 6.21-8.10eV to comply that the new dyes had good electron donating potentials. With a good electron injection potential of -1.47-1.74eV, aluminumcan be the best electrode, while Au is excellent towards a hole injection operation which had the potential range of 1.79-3.68eV. For Natural Bond Orbital (NBO) assessment, (N14)LP → (F16-F28)π* with stabilization energy of 42.55kcal/mol was noted for DTB4. Their Second order hyperpolarizability [Formula: see text] values as their Nonlinear Optical (NLO) response ranged between 59.16-232.11 debye-angstrom-1 which were almost 6 times higher than the reference DTB (8.47D). The NLO attributes has also shown that a dyes with its small bandgap was related with higher hyperpolarizability values. Because of the decreased reorganization frequencies, newly discovered derivatives withelectron transfer qualities might be comparable to or equivalent to those of commonly used electron transmission materials.

Deciphering the Role of Alkali Metals (Li, Na, K) Doping for Triggering Nonlinear Optical (NLO) Properties of T-Graphene Quantum Dots: Toward the Development of Giant NLO Response Materials.

Nanoscale nonlinear optical (NLO) materials have received huge attention of the scientists in current decades because of their enormous applications in optics, electronics, and telecommunication. Different studies have been conducted to tune the nonlinear optical response of the nanomaterials. However, the role of alkali metal (Li, Na, K) doping on triggering the nonlinear optical response of nanomaterials by converting their centrosymmetric configuration into noncentrosymmetric configuration is rarely studied. Therefore, to find a novel of way of making NLO materials, we have employed density functional theory (DFT) calculations, which helped us to explore the effect of alkali metal (Li, Na, K) doping on the nonlinear optical response of tetragonal graphene quantum dots (TGQDs). Ten new complexes of alkali metal doped TGQDs are designed theoretically. The binding energy calculations revealed the stability of alkali metal doped TGQDs. The NLO responses of newly designed complexes are evaluated by their polarizability, first hyperpolarizability (βo), and frequency dependent hyperpolarizabilities. The Li@r8a exhibited the highest first hyperpolarizability (βo) value of 5.19 × 105 au. All these complexes exhibited complete transparency in the UV region. The exceptionally high values of βo of M@TGQDs are accredited to the generation of diffuse excess electrons, as indicated by NBO analysis and PDOS. NCI analysis is accomplished to examine the nature of bonding interactions among alkali metal atoms and TGQDs. Our results suggest alkali metal doped TGQD complexes as potential candidates for nanoscale NLO materials with sufficient stability and enhanced NLO response. This study will open new doors for making giant NLO response materials for modern hi-tech applications.

Structural, spectral, DFT and Z-scan analysis of (E)-4-fluoro-N′(3,4,5-trimethoxybenzylidene)benzohydrazide for optoelectronics applications

ObjectiveTo synthesis a new Schiff base material (E)-4-fluoro-N′-(3,4,5-trimethoxybenzylidene)benzohydrazide (FBBH) by a slow evaporation method for nonlinear optical activity. MethodsSingle crystal X-ray diffraction (SCXRD), Fourier Transform Infrared (FTIR) spectroscopy, Nuclear magnetic resonance (NMR) spectroscopy, NBO analysis using DFT, third order non-linear optical (NLO) properties by Z-scan study. ResultsFrom NBO analysis, it is observed that the high energy ~ 197.82 kJ/mol transferred from donor N13→π*O16-C19 explores the hyperconjugation of –CONH– active group. The value of first-order hyperpolarizability ~ 23.73 × 10−30 esu was obtained for the FBBH compound which is 64 times greater than the reference molecule urea. The third order non-linear optical (NLO) properties of the FBBH molecule was evaluated from the Z-scan study. This study indicates that FBBH compound is one candididtae for optical limiters.

Synthesis, Single-Crystal XRD, Spectral and Computational Analysis of 2-(3,4-Dimethoxyphenyl)-1H-Phenanthro[9,10-d] Imidazole as Electron-Transport and NLO Material

A new Phenanthro-imidazole crystal, 2-(3,4-dimethoxyphenyl)-1H-phenanthro[9,10-d] was synthesized and characterized with spectral studies (IR, 1H-NMR, 13 C-NMR). Single Crystal X-ray and refinement studies reveals that the synthesized crystal system is monoclinic with P21/n space group and crystallographic data has been deposited in the Cambridge crystallographic data center with CCDC number: 2126693. RMSD values (Bond length = 0.035 Å and Bond angle=) and R-squared analysis (Bond length = 0.985 and bond angle = 0.990) reveals very good correlation between the experimental and theoretical structure. Analysis of frontier molecular orbitals and calculation of reorganization energy using DFT methods reveals that the crystals could be used as an electron transport material in OLED devices as the electron reorganization energy ( is comparatively low with a value of 0.373 eV. The computed value for the static first hyperpolarizability of the crystal was found to be 1.40023X10−of esu, which is four times higher than the standard value of urea and hence the crystal can be a potential candidate for future studies in non-linear optics.

The electronic structures and nonlinear optical properties of Alkali and Alkali earth metal atoms doped C6H6Cl6: A density functional theoretical study

The all-cis 1,2,3,4,5,6-hexafluorocyclohexane C6H6F6 (1) is a well-known molecule which has an unusually large molecular dipole moment (6.2 Debye), and plentiful novel excess electron compounds have been successfully designed on the basis of it recently. Inspired by 1, in this study, we tried to replace all the F atoms in molecule C6H6F6 with Cl atoms and obtained the all-cis 1,2,3,4,5,6-hexachlorocyclohexane C6H6Cl6 (2). By introducing alkali metal atoms and alkaline earth metal atoms, a novel series of alkalides and excess electron compounds, namely MA*+-2-MA− (MA* = Na, K; MA = Li, Na and K) and MA*-2-MAE (MA* = Na, K; MAE = Be, Mg and Ca), were theoretically constructed and studied in this work. Our results exhibit the apparent charge transfer in MA*+-2-MA− systems by NBO analysis. And these compounds all show good stability from the values of VIE and Gap. Especially, Na+-2-Li− compound exhibit the largest first hyperpolarizability value (3.4 × 106 au). The calculated results indicate these novel proposed species possess significantly large nonlinear optical responses. We hope this work will attract more experimental interests and efforts to design and synthesize new excellent NLO materials.

Electronic, Thermodynamic Properties, Nonlinear Optical Responses, and Molecular Docking Studies on Cephalexin

The topology analysis of electron localization function (ELF), localized orbital locator (LOL), the study of nonlinear optical properties, thermal properties, and biological activities of cephalexin have been performed using DFT/B3LYP and employing 6-311++G(d,p) basis sets. The Mulliken atomic charge on atoms has been calculated. The quantities describing nonlinear optical (NLO) properties like molecular polarizability (α), first hyperpolarizability (β), and second hyperpolarizability (γ) were comparable to the values of urea. The computed value of the second hyperpolarizability was found to be negative, which is an important feature for the system of controllable NLO devices. The thermodynamic properties like heat capacity (S), enthalpy (H), and entropy (S) are positively correlated with the temperature. Further, the title molecule shows good potentiality for binding with the selected target protein matrix metalloproteinase-2.

Influence of End-Capped Modifications in the Nonlinear Optical Amplitude of Nonfullerene-Based Chromophores with a D-π-A Architecture: A DFT/TDDFT Study.

Nonlinear optical (NLO) materials have several uses in many fields such as solid physics, biology, medicine, nuclear physics, and material research. Therefore, a series of nonfullerene-based derivatives (CC10D1–CC10D8) with a D−π–A configuration was planned for the NLO investigation using CC10R as the reference molecule with structural alternations at acceptor moieties. Natural bonding orbital (NBO), UV–vis spectra, frontier molecular orbitals (FMOs), global reactivity parameters (GRPs), transition density matrix (TDM), and density of states (DOS) were analyzed using the M06/6-311G(d,p) functional in chloroform solvent to understand the NLO responses of CC10R and CC10D1–CC10D8. The highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) band gaps of CC10D1–CC10D6 were illustrated to be lower than that of CC10R, with the larger bathochromic shift (726.408–782.674 nm) resulting in a significant NLO response. Along with the band gap, the FMO method also identified an efficient interfacial charge transfer from D to A moieties via a π-bridge, which was further supported by the DOS and TDM map. Moreover, NBO calculations demonstrated that extended hyperconjugation and strong internal molecular interactions were important in their stabilization. The dipole moment (μ), linear polarizability ⟨α⟩, hyperpolarizability (βtotal), and second-order hyperpolarizability (γtotal.) were studied for CC10R and CC10D1–CC10D8. Among all of the derivatives, CC10D2 was proven to be the most appropriate candidate because of its suitable NLO behavior such as being well-supported by a reduced band gap (2.093 eV) and having a suitable maximum absorption wavelength (782.674 nm). Therefore, CC10D2 was reported to have a greater value of first hyperpolarizability (208 659.330 a.u.) compared with other derivatives and CC10R. For the second hyperpolarizability, a greater value was obtained for CC10R (5.855 × 107 a.u.), and its derivatives showed results comparable to that of the parent chromophore for γtotal. This theoretical framework reveals that structural customization with different acceptor units plays a significant role in obtaining attractive NLO materials for optoelectronic applications.

Investigation of Barrier Potential, Structure (Monomer & Dimer), Chemical Reactivity, NLO, MEP, and NPA Analysis of Pyrrole-2- Carboxaldehyde Using Quantum Chemical Calculations

In this work, the structural conformation of pyrrole-2-carboxaldehyde was evaluated using potential energy surface (PES) scan employing DFT computations using B3LYP method with 6-311++G(d,p) level of basis set. The molecule assumed cis form in conformational ground state being more stable than the trans by 15.21 kJ mol−1 due to the orientation of the N–C–C = O dihedral angle. Existence of hydrogen bonds due to intra- and inter-molecular interactions was envisaged. The geometrical parameters of optimized monomeric and dimeric forms have been computed. The computational structural parameters of monomer are in good agreement with its experimental counterparts. The HOMO-LUMO energies were employed for determination of chemical reactivity descriptors. The electronic properties such as frontier molecular orbitals and Global reactivity descriptors were predicted using TD-DFT method. The local reactivity descriptors such as Fukui functions were investigated to determine the electrophilic and nucleophilic attacks within the molecule. The calculated first order hyperpolarizability value exhibited its suitability for non-linear optical applications. Furthermore, the electrophilic and nucleophilic regions of the molecule were studied by molecular electrostatic potential and Fukui functions. 1H and 13C NMR chemical shifts were evaluated using GIAO method employing the same level of theory. NPA analysis and thermodynamic parameters were also calculated.

Lanthanum doped corannulenes with enhanced static and dynamic nonlinear optical properties: A first principle study

In this work, lanthanum doping on corannulene (C20H10) buckybowls has been explored for their geometrical, electronic and nonlinear optical (NLO) properties via DFT simulations. The interaction energies of −21.75 to −40.01 kcal/mol reflect that A-D complexes are thermodynamically stable. The HOMO-LUMO energy gaps of designed complexes are decreased significantly up to 48.92%. A maximum charge transfer of 1.452 |e| is observed for complex A as revealed by natural bond orbital analysis. Non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analyses have confirmed the presence of various interactions in the complexes. The complexes are transparent in UV–Visible region and absorption maxima fall near infrared region (1123–2032 nm). The highest nonlinear optical response in terms of first hyperpolarizability value of 5.08 × 104 au is observed for complex C. The hyper-Rayleigh scattering (βHRS) and frequency dependent hyperpolarizability coefficients including electro-optical Pockel's effect and second harmonic generation are also computed theoretically.