Optical Polarizability Research Articles

Dry mass photometry of single bacteria using quantitative wavefront microscopy

Quantitative phase microscopy (QPM) represents a noninvasive alternative to fluorescence microscopy for cell observation with high contrast and for the quantitative measurement of dry mass (DM) and growth rate at the single-cell level. While DM measurements using QPM have been widely conducted on mammalian cells, bacteria have been less investigated, presumably due to the high resolution and high sensitivity required by their smaller size. This article demonstrates the use of cross-grating wavefront microscopy, a high-resolution and high-sensitivity QPM, for accurate DM measurement and monitoring of single microorganisms (bacteria and archaea). The article covers strategies for overcoming light diffraction and sample focusing, and introduces the concepts of normalized optical volume and optical polarizability (OP) to gain additional information beyond DM. The algorithms for DM, optical volume, and OP measurements are illustrated through two case studies: monitoring DM evolution in a microscale colony-forming unit as a function of temperature, and using OP as a potential species-specific signature.

Universal optical polarizability for plasmonic nanostructures

Optical spectra of small metal nanoparticles are dominated by surface plasmon resonance. In this Letter, a simple analytical model for optical polarizability of metal nanoparticles of arbitrary shape is presented.

Fano-Like Resonance from Disorder Correlation in Vacancy-Doped Photonic Crystals.

By preparing colloidal crystals with random missing scatterers, crystals are created where disorder is embodied as vacancies in an otherwise perfect lattice. In this special system, there is a critical defect concentration where light propagation undergoes a transition from an all but perfect reflector (for the spectral range defined by the Bragg condition), to a metamaterial exhibiting an enhanced transmission phenomenon. It is shown that this behavior can be phenomenologically described in terms of Fano-like resonances. The results show that the Fano's parameter q experiences a sign change signaling the transition from a perfect crystal exhibiting a reflectance Bragg peak, through a state where background scattering is maximum and Bragg reflectance reaches a minimum to a point where the system reenters a low scattering state recovering ordinary Bragg diffraction. A simple dipolar model considering the correlation between scatterers and vacancies is proposed and the reported evolution of the Fano-like scattering is explained in terms of the emerging covariance between the optical paths and polarizabilities and the effect of field enhancement in photonic crystal (PhC) defects.

Optical and optoelectronic properties of (Ge2S8)100-xTex thin films for IR optical device fabrication

A detailed study of the optical and optoelectronic properties of (Ge2S8)100-xTex thin films for optical device fabrication is described in the present paper. Thin films of melt-quenched chalcogenide samples were deposited, on ultrasonically cleaned glass substrates, employing thermal evaporation technique. Transmission spectra were used to calculate the refractive index (n) and extinction coefficients (k). The refractive index increases from 2.187 to 2.329 by adding Te = 0 to 12. Dispersion parameters are evaluated using the WDD single oscillator model. The dielectric parameters real (εr) and imaginary (εi), electric modulus (M) and dielectric loss (tan δ) are used to evaluate the relaxation process in different compositions of (Ge2S8)100-xTex thin films. To further grasp the importance of amorphous chalcogenide compositions, we compute their optical conductivity (σ*op), electronic polarizability (αp), plasma frequency (ωp), metallization parameter (M), and refraction losses (RL) in optical devices. The dependency of Te content on the nonlinear refractive index (n2) and third-order susceptibility (χ(3)) is also calculated by an empirical formula, and it is found that the value of n2 increases from 11.938 × 10−12 to 20.615 × 10−12 esu, and the value of χ(3) rises from 6.8 × 10−13 to 12.472×10−13 esu with the addition of denser and higher atomic radius elements Te in the Ge-S system. The overall composition of Ge17.6S70.4Te12 is suitable as all-optical parameters show the maximum values that can be used for optical device purposes.

Effect of CuO on physical, structural and optical properties of lithium borosilicate glasses

This paper reports the effect of copper on the physical, structural and optical properties of lithium borosilicate glasses with the composition of 50B2O3-30SiO2-(20-x) Li2O-xCuO (x = 2, 4, 6, 8, 10 mol %) synthesized by the conventional melt-quench technique. The prepared samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and UV–visible spectroscopy to study their structural and optical properties. Various physical parameters such as density, molar volume, oxygen packing density, ionic concentration and their inter-ionic distance are investigated. The band gap decreases from 3.64 to 2.70 eV with CuO doping into Li2O. The BO4 structural units change into BO3 units with the addition of CuO. The change in dielectric constant, extinction coefficient, refractive index and skin depth as a function of wavelength is also discussed. The theoretical optical basicity and oxide ion polarizability are found to increase with Li2O doping in place of CuO.

Synthesis, physico-chemical characterization and quantum chemical studies of 2, 3-dimethyl quinoxalinium-5-sulphosalicylate crystal

2,3-dimethylquinoxalinum-5-sulphosalicylate (MQSA) was synthesized and grown into single crystals by slowly evaporating the solvent in methanol at room temperature. According to the lattice parameters found by the SCXRD analysis method (a = 8.8031 (17) Å, b = 17.768(3) Å, c = 10.7979(16) and α = γ = 90°, β = 90.611 (7) °), the crystal belongs to monoclinic crystal system with the P21/n space group. Moreover, powder X-ray diffraction investigation supported the crystalline nature. The compound's UV–Vis spectra exhibited a CT-band with a wavelength maximum of 372 nm, as well as its NIR spectra revealed good optical transmittance in the visible region with a low cut-off wavelength of 376 nm and an optical band gap of 5.12 eV. Dual emission bands at 418 and 484 nm are observed in the PL emission spectra. The synthesized crystal was examined using FT-IR, FT-Raman, and NMR spectral methods. The crystal is thermally stable up to 274 °C, furthermore, TG-DTA and DSC methods were employed to study the degradation process. The second and third-order NLO efficiencies of the crystal was analyzed by Kurtz-Perry powder and Z-scan methods, respectively. The single crystal of MQSA is further studied through Hirshfeld surface analysis, fingerprint plots, and crystal voids analysis to understand the intermoleculiar interactions and individual atomic arrangements inside the crystal. The H…H and O…H/H…O interactions are greatly aided by crystal structure. Additionally, the quantum computational methods were used to assess several molecular level electronic properties, including molecular orbitals, molecular electrostatic potentials maps, linear polarizability and static third-order nonlinear optical (NLO) polarizability, which is a molecular-level NLO response property. The isotropic linear polarizability and NLO polarizability of MQSA are 29.99 × 10−24 esu and 28.45 × 10−36 esu, respectively, in the M06–2X/6–311G* method, which demonstrates the decent potential of the synthesized crystal for its use as NLO materials. Furthermore, the frontier molecular orbitals, molecular electrostatic potentials, and UV–Visible spectrum were calculated and discussed.

Optical basicity, polarizability and spectroscopic investigations of CuO doped TeO2–B2O3 glass system

A study of the spectroscopic properties, as well as polarizability and optical basicity of TeO2–B2O3 glasses doped with CuO using density, XRD, and UV–Vis analysis, is presented in this paper. The TeO2–B2O3 – CuO glasses are fabricated using the melt-quenching method. The glasses proved to be amorphous in nature from the XRD which was confirmed by the UV–Vis spectra. The peak observed in the pattern of the 0% CuO sample represents the presence of a crystalline phase of α-TeO2 and/or γ-TeO2. Important optical and physical parameters are discussed such as the refractive index (2.318–2.378), metallization criterion (0.4069–0.3919), optical basicity (0.7995–0.8057), electronic polarizability (0.2358–0.2410), linear dielectric susceptibility (0.3480–0.3704 esu), and third order non-linear dielectric susceptibility (1.466 × 1012–1.882 × 1012 esu). Based on the refractive index, metallization criterion, electronic polarizability, optical basicity, and dielectric susceptibility values, the glasses could present great potential applications in fiber optics and laser applications.

Geometrical Stability and Nonlinear Optical Properties of Crystallogen and Pnictogen Fullerene Analogues

The linear and nonlinear optical (NLO) properties of fullerene and fullerene-like structures, including crystallogen and pnictogen elements, are computed quantum mechanically. The tensors of optical polarizability, α, and second hyperpolarizability, γ, for a series of buckyball fullerene analogues, namely, Si60, Ge60, Sn60, Pb60, P60, As60, Sb60, and Bi60, are reported and analyzed. The eight considered nanocages are here classified into four categories: nanocages stabilized in the X60 form, including C60, As60, Sb60, and Bi60; nanocages that are not stabilized in the X60 form but are found to be stable in a distorted buckled b-X60 form, with X = Si and Ge; nanocages stabilized only in an exohedral decorated X60-Y60 form, X = Sn, Y = H or F; and finally nanocages that are not stable in either distorted or decorated form; however, their corresponding tabular nanotubes are found to be stable; such group includes P and Pb elements. A suggested nomenclature for the above-mentioned fullerenes is given for the first time, where many geometrical, energetic, and optical parameters are discussed extensively. These systems are energetically stable. The cohesive energies of Bi60 and Sn60-F60 range from -1.2 to -4.8 eV/atom and can be compared to -2.4 and -3.3 eV/atom from the corresponding 2D bismuthene and stanene monolayers, respectively. While bismuthellene, Bi60, shows vigorous optical responses compared to standard fullerene, the (9, 0) phosphorus nanotube gives not only enhanced polarizability and second hyperpolarizability but also an inducing first hyperpolarizability, β, which was null by symmetry in the case of spherical fullerenes. The proposed models are expected to be promising materials for optoelectronic and NLO applications.

Optical Trapping of a Single Molecule of Length Sub-1 nm in Solution

Optical Trapping of a Single Molecule of Length Sub-1 nm in Solution

Synthesis, crystal structure, Hirshfeld surface analysis, DNA binding, optical and nonlinear optical properties of Schiff bases derived from o-aminophenol

The current work focuses on the synthesis of the two new Schiff base ligands derived from o-aminophenol named 2-[(E)-(3-chlorophenyl)methylidene]amino-phenol (2AP3Cl) and 4-Chloro-2-(E)-[(2-hydroxyphenyl)iminio]methyl-phenolate (2AP5Cl). The synthesized Schiff bases were characterized by different Spectro analytical techniques like CHN, FT-IR, and NMR (1H and 13C) analysis. Moreover, a single crystal X-ray diffraction (SC-XRD) study was carried out for both compounds, which inferred that 2AP3Cl and 2AP5Cl adopted enol and keto tautomeric forms, respectively. The supramolecular assembly with respect to strong and comparatively weak non-covalent interactions was explored by Hirshfeld surface analysis. The interaction energy between molecular pairs, energy frameworks, and void analysis was performed to further investigate the crystal packing environment. Both compounds were screened for their DNA binding abilities. Moreover, quantum chemical methods were applied to study the electronic structure, linear and nonlinear optical (NLO) polarizabilities of the synthesized Schiff bases. The 2AP3Cl and 2AP5Cl molecules exhibited good NLO hyperpolarizability of 9.62 × 104 and 7.90 × 104 au., respectively. The calculation of molecular electrostatic potentials, 3-D visualization of frontier molecular orbitals, and their orbital gaps were also studied. Overall, reasonably good third-order NLO response properties were calculated, which show a decent potential of synthesized compounds for their potential for NLO applications.

Effect of thulium oxide on structural, refractive index, and optical band gap of bismuth-boro-tellurite glass system

The bismuth-boro-tellurite glass has been chosen by various analysts from all around the world due to its advantages and ability the improvement of glass technologies. This paper aims to study the structural and optical properties of the bismuth-boro-tellurite glass system with different amounts of thulium oxide as a glass dopant. Four glass sample from chemical composition of [(B2O3)0.25 (TeO2)0.75]0.75 [(Bi2O3)0.25]1-x [Tm2O3]x (x = 0.000, 0.005, 0.010, and 0.015 mol%) were prepared by melt-quenching method with suitable melting and quenching temperature. The Ultraviolet-Visible Spectroscopy (UV-Vis) was used for recording their optical absorption spectra. These optical absorption spectra were used to determine the optical band gap energy, refractive index, and polarizability of all glass samples. While the structural changes are observed using X-ray diffractometer (XRD) and Fourier Transform Infrared Spectroscopy (FTIR).

Effect of B2O3 and Li2O on vibrational, thermal and optical properties of 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (0 ≤ x ≤ 25 mol%) glasses

Bi2O3 based glasses have been proven as promising optical materials with regard to their 6 s2 lone pair electrons. By melt quenching, the highly thermal stable glasses 50Bi2O3-15PbO-(35-x)B2O3-xLi2O (where 0 ≤ x ≤ 25 mol%) were prepared. The short range order of the glasses was verified with XRD and DSC measurements. DSC analysis showed that thermal parameters varied non-linearly with increase of Li2O. Density (ρ), molar volume (Vm), oxygen packing density (OPD) and oxygen molar volume (Vo) were calculated and their compositional dependency was discussed in detail. Energy dispersive X-Ray (EDX) spectrometry analysis validated the stoichiometry of sample composition. FTIR analysis illustrated that the glass network comprise of BiO3, BiO6, BO3 and BO4 structural units together with non-bridging oxygens. The computed optical properties like optical band gap (Eopt), refractive index (n), Urbach energy (∆E), molar refraction (RM), metallization criterion (M) and oxide ion polarizability (αO2-) were observed to be non-linearly varied with the addition of Li2O. The interplay between the structural roles of Li2O and Bi2O3 was instrumental for the observed variations in all the properties. BiPBL4 glass showed the highest thermal stability (175 °C) and the high kgl value among the glass series. The incorporation of Li2O in presence of low mol% of B2O3 with Bi2O3-PbO endowed these glasses to have the low phonon energy. The analysis carried out in this work showed that these glasses might useful for optoelectronic devices and optical fiber drawing applications.

Insights into solvent effects on molecular properties, physicochemical parameters, and NLO behavior of brinzolamide, a bioactive sulfonamide: A computational study

In this study, quantum chemical calculations performed on brinzolamide (BZ), a sulfonamide derivative widely used as an antibacterial and antifungal drug, are presented. The molecular geometry optimizations of BZ were calculated by using both B3LYP functional and HF method with the 6-31G (d, p) basis set via Gaussian software. Since solvent phase behaviors are extremely important especially for drug molecules, calculations were renewed for BZ in ten different solvent environments. Universal solvation model SMD (Solvent Model based on Density) was utilized for solvent phase simulations. Mulliken and natural atomic charges, frontier molecular orbital (FMO) energies, quantum chemical descriptors were studied in detail according to solvent and method variation. In addition, the partition coefficient (logPow) value, which is an important parameter for the activity of the drug candidates, was theoretically estimated according to the relevant formula through the computed values for the water and 1-octanol phases for each methodology. The slightly lipophilic character of the BZ molecule was supported by the obtained values and the molecular lipophilicity potential map prepared by means of Molinspiration Galaxy 3D Structure Generator v2018.01 beta program. In the nonlinear optical (NLO) property analysis, dipole moment (μtot), mean polarizability (αtot), anisotropic polarizability (Δα), and mean first-order hyperpolarizability (βtot) values of BZ and the solvent effect on these values have been reported. Last, the interaction energies between donor and acceptor orbitals were calculated by the analysis of natural bond orbitals, and the obtained results were summarized.

A Quantum Chemical Study of Outstanding Structural, Electronic and Nonlinear Optical Polarizability of Boron Nitride (B12N12) Doped with Super Salt (P7BaNO3)

A Quantum Chemical Study of Outstanding Structural, Electronic and Nonlinear Optical Polarizability of Boron Nitride (B12N12) Doped with Super Salt (P7BaNO3)

Study of ionic conduction, dielectric relaxation, optical and electrochemical properties of AgPO3/graphene glasses for magnesium battery applications

Developing suitable cathode material for alkali ion batteries is the most significant challenge facing commercialization. The effect of graphene nanoplatelets (GNP) on the physical and optical properties of AgPO3 glass is demonstrated. For the first time, AgPO3/Graphene glasses have been synthesized by melt-quenching method to assess the physical and the electrochemical performance as a cathode for a Magnesium ion battery. The complex impedance method determines bulk conductivity; the bulk conductivity increases with increasing temperature and graphene content. AgPO3_2 wt%GNP (sample 2) shows the optimum stoichiometric ratio with linear conductivity-temperature growth up to fast-ionic conductivity ∼ 1.79×10−2 (ohm. cm)−1 at 150 °C. The study of frequency dependence of both dielectric constant and dielectric loss have been explained based on ion hopping beside the ionic polarization mechanism. Optical properties such as the refractive index, optical energy gap, molar refractivity, molecular polarizability, dispersion, and oscillator energy of AgPO3 glass with different graphene nanoplatelets are investigated. The data reveal the lowest energy gap for the glass sample (AgPO3/2 wt%GNP). On the contrary, the values of refractive index, dispersion energy, molar refractivity and molecular polarizability are the highest for (AgPO3_2%wt%GNP) sample. The coin cell has been fabricated with the cell configuration Mg//electrolyte//AgPO3 and Mg//electrolyte//AgPO3_2 w%GNP. The cell with AgPO3_2 wt% GNP electrode has a high initial discharge capacity of ∼187 mAh/g compared with AgPO3 electrodes of ∼100 mAh/g.

Tuning of optoelectronic and transport properties of zinc-blend magnesium chalcogenides through doping of Hg atom(s): The mBJ-GGA+U based first-principle calculations

The present first-principle calculations have established the possibility of tuning of structural, optoelectronic and transport properties of direct-band-gap and optically active zinc-blend magnesium chalcogenides through doping of Hg atom(s) at different compositions. The process results a set of thermodynamically stable, direct-band-gap and optically active HgxMg1-xS, HgxMg1-xSe and HgxMg1-xTe semiconductor ternary alloys. Non-linear enhancement in lattice constant (a0), but reduction in fundamental band-gap (Eg) takes place in each system with increasing Hg-composition (x). Electrons and light holes possess much smaller effective-mass compared to heavy holes in each specimen. Calculations show positive Seebeck coefficient and hence p-type conduction property of each ternary alloys. Calculated electronic figure-of-merit shows that ternary alloys are suitable for efficient thermoelectric applications beyond 900 K temperature. Electronic excitations from valence chalcogen-p level to Mg-4s, 3p and Hg-7s levels of conduction band region of band-structure near Fermi-level put significant contributions in diverse optical phenomenon in the UV region, which lead to their compatibility in fabricating diverse UV optoelectronic devices. Oscillator strength, optical energy-gap, skin-depth, optical electronegativity difference, electronic polarizability and diamagnetic susceptibility of each of the considered specimens are also calculated in the present study.

The Computational Study, 3D-QSAR, and Molecular Docking Study of 2-Amino 5-Methyl Pyridine

The indeed optimized structure of the 2-Amino 5-Methyl Pyridine (2A5MP) and its minimum energies were analyzed by using B3LYP functional with B3LYP/6-311++G (d, p) basis set. The first hyperpolarizability (β), polarizability (α), and dipole moment (μ) of the compound were computed and the results were reported. The Mulliken charges, atomic polarizability tensor (APT) charges and HOMO-LUMO energy difference were calculated. This energy difference illustrates the properties of optical polarizability, chemical hardness/softness, and kinetic stability/reactivity of a molecule. NBO analysis was executed to know the transfer of electrons within the molecule and molecular electrostatic potential (MEP) analysis was also performed. The docking procedure was accomplished between 2- amino 5-methyl pyridine and rigid protein receptors. Druglikeness principles are based on the rules of Lipinski and Veber appraise that the title molecule had the ideal physicochemical and pharmacokinetic properties to be a good drug candidate orally. The docking studies were carried out and analyzed in order to understand the binding mode of the titled compound and it was found to have a binding energy of −3.32 kcal/mol.

Synthesis, single-crystal X-ray diffraction, NLO and DFT studies of centrosymmetric 4-amino-3,5-dimethyl-1H-pyrazolium citrate monohydrate salt

An organic salt compound 4-amino-3,5-dimethyl-1H-pyrazole (ADMP) has been combined with citric acid and crystallised at room temperature, forming a new molecular salt 4-amino-3,5-dimethyl-1H-pyrazolium citrate (ADMPCA) as a monohydrate. The compound was then structurally characterised by single-crystal X-ray diffraction (XRD), spectral analysis of FTIR, NMR and UV, and thermal studies. The structural analysis has shown that the ADMP molecules participate in the dominant hydrogen-bonding patterns forming a ladder-like structure via charge-assisted N+–H···O, O–H···O and N–H···O hydrogen bonds. The Hirshfeld surface analysis has been performed to understand the importance of intermolecular interactions in the stability of the salt structure. Theoretical studies were performed employing the DFT/B3LYP/6-311++G(d,p) level of theory to investigate Non-linear optical (NLO) behaviour, first-order hyperpolarisability, dipole moment and polarisability. The molecular properties, such as natural charge analysis and MESP analysis, were also explored in the present study.

Optical basicity and electronic polarizability of Sm3+-doped silica glass prepared by sol–gel process

The SiO2-doped with Sm3+ of various concentrations (100-x) SiO2:xSmO3/2 (where x = 0.5, 1.0, 1.5, 2.0 mol%) have been prepared by sol–gel method and non-linearity was studied. The physical parameters like density, molar volume, total molecular weight, refractive index, reflection loss, molar refractivity, energy gap, molar electronic polarizability, dielectric constant, optical dielectric constant, electronic polarizability, ionic concentration, polaron radius, inter ionic distance, field strength and optical basicity were obtained. The structural information was acquired through Fourier transform infrared (FTIR). On the basis of the measured values of the density and refractive index, the Sm3+ ion concentration in glasses, the polarizability of oxide ions and optical basicity were found to increases with rare earth (RE) ions concentration. Theoretically the oxide ion polarizability increases with the refractive index and decrease with energy gap. The theoretical value of molar refraction, electronic polarizability, oxide ion polarizability and metallization criterion were calculated by using Lorentz-Lorenz equation. Theoretical optical basicity of the glasses is evaluated based on equation proposed by Duffy and Ingram. The dielectric constant and optical dielectric constant were found to increase with increase in RE ions concentration.

Insighting the functionally modified C60 fullerenes as an efficient nonlinear optical materials: A quantum chemical study

It is well-known that π-conjugation plays an important role to tune the nonlinear optical (NLO) response of donor-π-conjugated-acceptor compounds. Fullerenes (C60) are one of a few compounds who are abounded with π-conjugation and perhaps are the largest π-conjugation compounds. In the present study, we systematically designed C60 derivatives (2 (fulleropyrrolidine) and 2a-2c (fulleropyrrolidine tetrathiafulvalene derivatives where 2a, 2b and 2c are with n = 0, n = 1 and n = 2) through the use of pyrrolidine and tetrathiafulvalene moieties. We applied density functional theory (DFT) methods to calculate their respective geometrical structures, electronic properties, linear and nonlinear optical response properties along with their respective UV–Visible spectra using CAM-B3LYP functional and 6-31G* basis set. The isotropic polarizability (αiso) and anisotropic polarizability (αaniso) of 2c was found to be 131.52 × 10-24 and 47.01 × 10-24 esu, respectively. Amongst our designed compounds, the maximum second-order nonlinear optical polarizability amplitude (β//) of 2c was found to be 15.69 × 10-30 esu. Interestingly, 2c shows the highest third-order nonlinear polarizability amplitude <γ> of 284.29 × 10-36 esu that is about three times higher than parent compound 1. Additionally, frontier molecular orbitals (FMOs), molecular electrostatic potential maps (MEPs), transition density matrix (TDM) analysis indicate more effective charge redistribution from donor moiety to acceptor fragments. The density of states (DOS) diagrams reveal distinct electronic contributions of various fragments in the formation of HOMO and LUMO orbitals resulting in efficient intramolecular charge transfer (ICT) and robust third-order NLO response properties of functionalized fullerene derivatives. The current study may arouse the attention of the scientific society to utilize the extensive π-conjugation of functionalized fullerenes for designing efficient NLO materials.