Lorentz-Lorenz Equation Research Articles

Experimental and computational insight in molecular interactions of imidazolium based deep eutectic solvent with selected alcohols (C1 and C2)

The experimental thermophysical properties (densities (ρ), speed of sound (u) and refractive (nD) indices) of binary mixtures containing 1:3 mol ratio of [1-butyl-3-dimethylimidazolium chloride to ethylene glycol] [BMIM]Cl: EG], deep eutectic solvent (DES), with selected alcohols (methanol and ethanol) were measured. The measurements of the binary mixtures and the pure solvents were conducted at temperatures ranging from (293.15 to 313.15) K in the interval of 5 K and at ambient pressure using an Anton Paar densitometer. Thermodynamic properties such as excess molar volumes (VmE), intermolecular free length (Lf), isentropic compressibilities (ks), deviation in isentropic compressibilities (Δks) and deviation in refractive indices (ΔnD) were computed from the measured data of physical properties. These excess thermodynamic properties are utilized to investigate the intermolecular interactions occurring between imidazolium DES and methanol or ethanol. Geometry optimization calculations were undertaken using Density Functional Theory (DFT) to model the structure of DES with a 1:1 mol ratio employing the B3LYP-D3 functional and a basis set of 6–31G++**. The DFT results revealed that the interaction energies within the DES in the presence of solvent favoured the formation of the complex. Furthermore, interrogation of the optimized structures at molecular level showed that the interactions were mediated by the electrostatic ionic bonding with the co-solvent playing a significant role in solubility. The excess molar volumes of binary mixtures were correlated using the Lorentz-Lorenz equation, and the densities and refractive indices were predicted using the Lorentz-Lorenz equation. The interaction energies and electrostatic interactions between the different solvents were predicted using quantum mechanics. The experimental data was found to be in good agreement with the theoretical data for the measured properties as well as the computational predictions of the stability of the systems.

Tailoring refractive index dispersion in ionic liquids: The influence of charge delocalization in cations

In this work, we study the contributions that different molecular blocks have in the wavelength-dependence of the refractive index in ionic liquids. The ionic liquids chosen for this work are combinations of the bis(trifluoromethylsulfonyl)imide anion with cations based on four different heterocycles with different extents of charge delocalization. The analysis is performed in terms of the experimental electronic polarizability, which is obtained by combining measurements of refractive index curves and densities via the Lorentz-Lorenz equation. Exploiting the additivity of electronic polarizability in ionic liquids, the contribution of the anion and the heterocycles of the cations is separated from that of the alkyl chains. Our results show important differences in these contributions, revealing a key influence of the charge delocalization in the cationic rings on the behavior of the refractive index dispersion. The understanding of how different parts of ionic liquids affect their refractive index dependence on wavelength would allow to gain precise control of this magnitude, enabling the development of customized optical materials for diverse applications in photonics and sensing technologies.

Thermodynamic properties, electrochemical properties, and interaction behaviors of quaternary ammonium salts-based deep eutectic solvents

To gain a deeper understanding of the formation mechanism for quaternary ammonium salts-based deep eutectic solvents (DESs), it is of great significance to investigate the interaction between hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA), as well as their physicochemical properties. In this study, tetrapropylammonium bromide (TPAB) or tetrabutylammonium bromide (TBAB) as HBA and malonic acid (MA) as HBD with a molar ratio of 1:1 or 1:1.5 were to synthesize four DESs of [TPAB]:[MA]-1, [TPAB]:[MA]-1.5, [TBAB]:[MA]-1 and [TBAB]:[MA]-1.5. The thermodynamic properties, electrochemical properties, and interaction behaviors of these DESs were investigated. The thermodynamic parameters of the standard entropy, lattice energy, molar refraction, molar polarization, and molar electrical conductivity for all DESs were calculated in terms of the Glasser’s classical theory, the molar surface Gibbs energy definition, the molar electrical conductivity definition, and Lorentz-Lorenz equation. Through linear scanning curve tests based on the three-electrode method, electrochemical potential windows (EPW) of all DESs were significantly higher than 2 V. Furthermore, according to DFT calculation and COSMO-RS theoretical model, the sequence of interaction strength for quaternary ammonium salts-based DESs was arranged as follows: [TBAB]:[MA]-1 > [TPAB]:[MA]-1 > [TBAB]:[MA]-1.5 > [TPAB]:[MA]-1.5. These fundamental theoretical studies help to provide significant theoretical reference value for the design of DESs with special properties, and promote the application range of DESs.

Structural and spectroscopic correlation in barium-boro-tellurite glass hosts: effects of Dy2O3 doping

In this study, a series of barium-boro-tellurite glass hosts with varying concentration of Dy2O3 doping (0 to 1.25 mol%) were made by melt-quenching method. A study was conducted to investigate how Dy2O3 dopants affect the physical and spectroscopic traits of glasses. Raw materials including barium oxide (BaO), tellurium dioxide (TeO2), boron oxide (B2O3), and dysprosium oxide (Dy2O3) were used to produce these glasses. XRD patterns of the samples showed a broad hump and absence of long-range periodic lattice arrangements, indicating their amorphous nature. The Raman spectral analyses displayed the various vibration modes where the most intense band caused by BaO vibrations at 300 cm-1 and 450 cm-1 corresponding to the symmetric stretching vibration mode of Te–O–Te intra-chain bridges. The peak at 750 cm-1 was due to TeO4 and Te-O-Te vibration modes. The value of optical band gap energy was decreased from 3.155 to 2.1894 eV and then increase at higher Dy2O3 level (0.75 to 1.25 mol%). At Dy3+ contents between 0.25 to 1.25 mol% seven absorption bands were observed at 390, 424, 452, 750, 797, 895 and 1092 nm due to the electronic transitions in Dy3+. The glass refractive indices were raised from 2.3563 to 2.6584 and then decreased at higher Dy2O3 contents which was mainly because of the generation of more bridging oxygen (BO) in the glass matrix. The value of glass electronic polarizability and oxide ions polarizability calculated using LorentzLorenz equation showed a decrease with the rise of Dy2O3 contents, which was ascribed to the presence of fewer non-bridging oxygen (NBO). The optical basicity of the proposed glass hosts was calculated using Duffy and Ingram equation which was decreased with the increase of doping contents. In addition, the optical transmission was increased and reflection loss was reduced with increasing Dy+3 levels. The value of metallization parameter below 1 proved the true amorphous nature of the prepared samples. All the glasses revealed blue and yellow photoluminescence emission peaks due to 4F9/2→ 6H15/2, and 4F9/2 →6H13/2 transitions in Dy3+, respectively. The proposed glass compositions may be beneficial for the advancement of solid-state lasers.

Application of Metal Oxide in Litho-Vanadium Glasses Containing Non-Magnetic Metal Ions: Physical and Optical Properties Analysis

Sodium-modified litho-vanadium glasses containing non-magnetic Aluminium ions of composition 50Li2CO3 - (30-X) Na2 CO3- 20V2O5 -xAl2O3 (30 ≤ x ≥ 5) (LNVA) glasses were prepared by melt quenching technique. The density of the glass samples was measured and found to increase with the Aluminium content of the glass matrix. The measured values of refractive index and polaron radius of the glass network show opposite behaviour with an increase of Aluminium content. Through band gap energy and refractive index, Oxide ion polarizability and electronic polarizability were determined by using the Lorentz-Lorenz equation. The value of Oxide ion polarizability and electronic polarizability is found to be decreased with decreasing band gap energy and increasing refractive index. The value of optical basicity was measured using electronic polarizability and is found to be decreased with decreasing inter-nuclear distance. The band gap energy values of the glass network were found to decrease from 3.241 to 2.134 eV. The metallisation criterion of the glass material was calculated and found to decrease with Aluminium content.

Investigation of intermolecular interactions of l-Valine and l-Phenylalanine with muscle relaxant drug mephenesin molecule prevalent in aqueous solution by various physico-chemical methods at T=298.15K–313.15K

A complete chemical analysis of significant intermolecular interactions of l-Valine (L-Val) and l-Phenylalanine (L-Phe) with Mephenesin (MEPN) molecules in aqueous solution has been studied by different physicochemical methodologies at various temperatures (T = 298.15 K–313.15 K at an interval of 5 K) and concentrations (0.001 mol kg−1, 0.003 mol kg−1, 0.005 mol kg−1) of aqueous MEPN solution. The limiting apparent molar volume (φV0) and experimental slope (SV*) values are found from the equation of Masson, viscosity A and B-coefficient determined using the equation of Jones-Doles, molar refraction (RM) and limiting molar refraction (RM0) derived by the Lorentz-Lorenz equation, express that in our experimental solution of amino acids (AAs) in aqueous MEPN, the solute-solvent interaction predominates over the solute-solute and solvent-solvent interactions for these ternary solutions. These are also justified by the measurement of various thermodynamic parameters, free energy of activation of viscous flow per mole of solvent(Δμ1°#) and solute (Δμ2°#), activation of viscous flow of enthalpies (ΔH°#) and entropies (ΔS°#). The characteristics of structure-breaking of solutes in the aqueous drug solution have been identified by Hepler's method and dB/dT value. The spectroscopic methods like UV–visible and proton-NMR studies help to explicate the strong AA-MEPN interactions in the solution phase and obtain a good correlation with theoretical studies. Theoretical investigations are checked to authenticate the experimental observations and according to both studies, L-Phe-MEPN interaction is greater than L-Val-MEPN interaction. The experimental and correlated research data are useful for the development of model combinations of AAs with drug molecules in pharmaceutical and medicinal chemistry.

Neutral polymer-pseudo polyelectrolyte transition of a post irradiated polymer dissolved in water

The purpose of this study is to study the conformation transition of a post irradiated polymer dissolved in water. In fact, polyvinylpyrrolidone (PVP) in powder(Mw = 1.300.000 g/mol), is irradiated with various doses, D, ranged from 0.3 to 50 kGy of 60Co-gamma. The irradiated polymer, PVP*, is dissolved in water to obtain post irradiated solutions of different concentration. After the stabilization of the obtained solutions (48 h), refractometry and viscosity measurements, are used to characterize the post irradiated aqueous solutions at 25 °C. The specific volume of PVP* dissolved in water was determined according modified Lorentz-Lorenz and Gaston-Dale equations, showing two dependence on the dose, D. For D ≤ Dc = 20 kGy, the specific volume increases and for D ≥ Dc, the specific volume decreases. The reduced viscosity of PVP*(Mw = 1.300.000 g/mol) aqueous solution permits to delimit the dilute and semi dilute regimes concentration and deduce the overlapping concentration, C*PVP*(D), which found to be insensitive to the dose value. For D < Dc, the intrinsic viscosity PVP* dissolved in water is determined according a modified Huggins equation and so the irradiated polymer behaves as neutral polymer. However, when D = DC the intrinsic viscosity values calculated according modified Fuoss and Fedors equations are very close and the irradiated polymer behaves as a polyelectrolyte in water. For D > Dc, the modified Fedors equation describes perfectly the evolution of the reduced viscosity versus irradiated polymer concentration. So, PVP* behaves as a polyelectrolyte in water and a neutral polymer – pseudo polyelectrolyte transition occurs under gamma irradiation effect. The irradiated polymer molar mass, MwPVP∗(D), was determined by comparing its intrinsic viscosity to these established according the Mark Howink Shakurada equation. MwPVP∗(D) decreases by increasing the dose value, which confirm the scission the polymer chain under gamma irradiation effect.

Study on temperature-dependent growth characteristics of germanium oxide film by plasma-enhanced atomic layer deposition

Germanium oxide (GeOx) films were grown by plasma-enhanced atomic layer deposition (PE-ALD) at 70, 130, 190 and 250 °C, using tetrakis (dimethylamino)-germanium as a precursor and O2 plasma as a reactant. For GeOx film grown at 250 °C, a relatively low growth-per-cycle (GPC) of 0.55 Å/cycle and high refractive index of 1.73 was observed as compared to the GPC and refractive index for the films grown at 70, 130, and 190 °C.Meanwhile, the areal portion of the germanium monoxide (GeO) peak to germanium dioxide (GeO2) in the Ge 3d core-level spectra of X-ray photoelectron spectroscopy increased proportional to the refractive index of the film. When estimating the mean molar mass of the GeOx films from the Lorentz-Lorenz equation, low molar mass was obtained from the GeOx film grown at 250 °C indicating germanium monoxide bond formation in the film.As the PE-ALD grown GeOx films exhibited high densities of about 3.5 g/cm3 almost close to the typical density value (3.6 ∼ 3.7 g/cm3) of germanium oxide film, low water-etch rates of 5 ∼ 10 nm/s were achieved for the PE-ALD grown GeOx films, compared to the reported etch rates of 60 ∼ 100 nm/s for germanium dioxide films. In summary, PE-ALD process for growing GeOx films has the advantage of obtaining high film density with controllable water-etch rate.

Exploration of Diverse Interactions of l-Methionine in Aqueous Ionic Liquid Solutions: Insights from Experimental and Theoretical Studies.

Here, we have investigated some physicochemical parameters to understand the molecular interactions by means of density (ρ) measurement, measurement of viscosity (η), refractive index(n D) measurement, and conductance and surface tension measurements between two significant aqueous ionic liquid solutions: benzyl trimethyl ammonium chloride (BTMAC) and benzyl triethyl ammonium chloride (BTEAC) in an aqueous l-methionine (amino acid) solution. The apparent molar volume (Φv), coefficient of viscosity (B), and molar refraction (R M) have been used to analyze the molecular interaction behavior associated in the solution at various concentrations and various temperatures. With the help of some important equations such as the Masson equation, the Jones-Doles equation, and the Lorentz-Lorenz equation, very significant parameters, namely, limiting apparent molar volumes (Φv 0 ), coefficient of viscosity (B), and limiting molar refraction (R M 0), respectively, are obtained. These parameters along with specific conductance (κ) and surface tension (σ) are very much helpful to reveal the solute-solvent interactions by varying the concentration of solute molecules and temperature in the solution. Analyses of Δμ1 0#, Δμ2 0#, TΔS 2 0#, ΔH 2 0#, and thermodynamic data provide us valuable information about the interactions. We note that l-Met in 0.005 molality BTEAC ionic liquid at 308.15 K shows maximum solute-solvent interaction, while l-Met in 0.001 molality BTMAC aqueous solution of ionic liquid at 298.15 K shows the minimum one. Spectroscopic techniques such as Fourier transform infrared (FTIR), 1H-NMR, and UV-vis also provide supportive information about the interactions between the ionic liquid and l-methionine in aqueous medium. Furthermore, adsorption energy, reduced density gradient (RDG), and molecular electrostatic potential (MESP) maps obtained by the application of density functional theory (DFT) have been used to determine the type of interactions, which are concordant with the experimental observations.

Thermal Lens Measurements of Thermal Expansivity in Thermosensitive Polymer Solutions

The weak absorption of a laser beam generates in a fluid an inhomogeneous refractive index profile acting as a negative lens. This self-effect on beam propagation, known as Thermal Lensing (TL), is extensively exploited in sensitive spectroscopic techniques, and in several all-optical methods for the assessment of thermo-optical properties of simple and complex fluids. Using the Lorentz-Lorenz equation, we show that the TL signal is directly proportional to the sample thermal expansivity α, a feature allowing minute density changes to be detected with high sensitivity in a tiny sample volume, using a simple optical scheme. We took advantage of this key result to investigate the compaction of PniPAM microgels occurring around their volume phase transition temperature, and the temperature-driven formation of poloxamer micelles. For both these different kinds of structural transitions, we observed a significant peak in the solute contribution to α, indicating a decrease in the overall solution density-rather counterintuitive evidence that can nevertheless be attributed to the dehydration of the polymer chains. Finally, we compare the novel method we propose with other techniques currently used to obtain specific volume changes.

Optical and physical properties of annealed amorphous niobium oxide thin films.

The physical and optical properties of coatings deposited using physical vapor deposition techniques exhibit changes during post deposition annealing. Optical properties including the index of refraction and spectral transmission vary when coatings are annealed. Physical and mechanical properties such as thickness, density, and stress are also impacted by annealing. In this paper, we study the source of these changes by examining the impact of 150-500°C annealing on N b 2 O 5 films deposited using thermal evaporation and reactive magnetron sputtering. Models based on the Lorentz-Lorenz equation and potential energy considerations explain the data, and rationalize conflicts between previously reported results.

Investigation of optical properties and radioactive attenuation parameters of doped tungsten oxide soda lime silica SLS waste glass

The optical properties and radioactive attenuation parameters of doped tungsten oxide soda-lime-silica (SLS) waste glass were investigated in the current work. A novel series of lead-free transparent glass samples were manufactured with the possibility of developing radiation-absorbing glass shielding materials. The glass composition is WO3–Bi2O3–ZnO–B2O3-SLS. A new approach was employed in the utilization of soda-lime-silica (SLS) glass as an alternative for pure silicon dioxide having 74.1% of SiO2 and other elements in it. The optical properties were investigated with the help of a UV–Visible Spectrophotometer. The results for the optical properties showed that when WO3 content is increased in the glass structure, the Urbach energy ΔE and refractive index n, increase from 0.337 to 0.431 and 2.84 to 2.94 respectively, the optical basicity Λ also increase with the increase in WO3 while the energy optical band gap Eopt registered a decrease. The metallization criterion (M) confirmed that the current glass samples are nonmetallic (insulator) because Rm/Vm < 1 which is confirmed in the condensed matter theory in the Lorentz–Lorenz equations. Moreover, the theoretical radiation shielding parameter results indicate that the linear attenuation coefficient μ and Zeff were increased with an increase in WO3. It can be seen also that the relationship between the μ and HVL is an inverse one; larger values of μ result in lesser thickness of the HVL. Whereas, as the WO3 concentration increases, the half-value layer HVL decreases. The results of this study demonstrate that the glass samples are harmless, transparent to visible light, and effective radiation shielding materials.

A New Compartmentalized Scale (PN) for Measuring Polarity Applied to Novel Ether-Functionalized Amino Acid Ionic Liquids.

Functionalized and environmentally friendly ionic liquids are required in many fields, but convenient methods for measuring their polarity are lacking. Two novel ether-functionalized amino acid ionic liquids, 1-(2-methoxyethyl)-3-methylimidazolium alanine ([C1OC2mim][Ala]) and 1-(2-ethoxyethyl)-3-methylimidazolium alanine ([C2OC2mim][Ala]), were synthesized by a neutralization method and their structures confirmed by NMR spectroscopy. Density, surface tension, and refractive index were determined using the standard addition method. The strength of intermolecular interactions within these ionic liquids was examined in terms of standard entropy, lattice energy, and association enthalpy. A new polarity scale, PN, is now proposed, which divides polarity into two compartments: the surface and the body of the liquid. Surface tension is predicted via an improved Lorentz-Lorenz equation, and molar surface entropy is used to determine the polarity of the surface. This new PN scale is based on easily measured physicochemical parameters, is validated against alternative polarity scales, and is applicable to both ionic and molecular liquids.

Physicochemical investigation of L-Asparagine in green solvent arrangements with the manifestation of solvation consequences

Solution behaviour prevailing in L-Asparagine in two aqueous ionic liquid solutions, namely (Benzyl tri–methyl ammonium chloride; Benzyl tri-ethyl ammonium chloride) have been studied by investigation of physico-chemical parameters; density, viscosity, refractive index, conductance and surface tension measurement respectively. The nature of interactions occurring in the solution have been calculated on the basis of apparent molar volume, viscosity A and B-coefficient, molar refraction at 298.15K,303.15K,308.15K and at 0.001m, 0.003m, 0.005m concentrations. The limiting apparent molar volumes (φV0) obtained from Masson equation, viscosity parameters, A and B coefficients obtained from Jones-Doles equation, Molar refraction (RM) from the Lorentz-Lorenz equation that describe the nature of solute-solute and solute-solvent interactions in the solution. Specific Conductance of the experimental solution, which applied to ascertain the ionic nature of the system. The different thermodynamic data, Δμ10≠, Δμ20≠, ΔH0≠, and TΔS0≠ also suggest the presence of strong interactions in the studied systems. The various types of interactions existing among amino acids in presence of ionic liquids which are the protein backbone would advance a many-dimensional challenge in the arena of solution chemistry. Studies of such systems could be forward-thinking further using the correlated results of the investigation.

Molecular Interactions of Some Bioactive Molecules Prevalent in Aqueous Ionic Liquid Solutions at Different Temperatures Investigated by Experimental and Computational Contrivance

The solute –solvent interaction between ionic liquids (ILs) and amino acids (AA) in aqueous media plays a significant role for the optimization of a number of important biotechnological processes. l-Valine and l-Proline (two solute molecules) interact with an ionic liquid (Benzyltributylammonium chloride) in aqueous medium. Based on the different parameters such as apparent molar volume, viscosity B-coefficient, molar refraction, molar conductance at different temperatures and different concentrations from density, viscosity, refractive index, conductance measurements have been used to explain the molecular level interactions which was supported by NMR and UV–Vis studies. Using Masson equation, the experimental slopes and the limiting apparent molar volumes are obtained which explain the solute-solute and solute-solvent interactions. Hepler's technique and dB/dT values have been used to examine the structure-making and structure-breaking nature of the solutes in the solvents. Viscosity parameters, A and B obtained from Jones-Doles equation explained the solute-solute and solute-solvent interactions in the solution. Lorentz-Lorenz equation has used to calculate the molar refraction. The specific conductance also explained the interaction properties. Further the findings have been supported by NMR study of the solutions and also considerable amount of theoretical analysis has been done which was in good agreement with the experimental result. The behavior of many other bio-molecules can be explained by considering amino acids as model and the mechanism has been extended to elucidate the behavior of other (biological) systems. In our findings we were emphasized on the nature of solute–solvent interactions and the presence of structural effect on the solvent in solution to analyze the molecular-level interactions prevalent in the systems.

Surface tension, viscosity and electrical conductivity characteristics of new ether-functionalized ionic liquids

1-(2-Ethoxyethyl)-3-methylimidazolium acetic acid ([C2OC2mim][OAc]) and 1-(2-ethoxyethyl)-3-methylimidazolium lactic acid ([C2OC2mim][Lac]) ether-functionalized ionic liquids (ILs) were prepared. In terms of the standard addition method, the experimental data of density, surface tension, refractive index, viscosity and electrical conductivity of two pure ILs were obtained. Using the definition of the molar surface Gibbs energy with Lorentz-Lorenz empirical equation, the surface tensions of ether-functionalized ILs were estimated, and their predicted values were in good agreement with the experimental values. According to the Vogel-Fulcher-Tamman (VFT) equation, the variation tendency between viscosity (or electrical conductivity) and temperature of [C2OC2mim][OAc] and [C2OC2mim][Lac] was studied. The variation trend of the viscosity was opposite to electrical conductivity. Namely, the viscosity gradually decreased and electrical conductivity gradually increased with increasing temperature. The results indicated that VFT equation had an enormous application range for fitting the viscosity and electrical conductivity of ether-functionalized ILs. The activation energies of [C2OC2mim][OAc] and [C2OC2mim][Lac] were estimated by Arrhenius empirical equation. The calculated results indicated that [C2OC2mim][Lac] (Eη means the activation energy, Eη = 41.24 kJ·mol−1) was larger than [C2OC2mim][OAc] (Eη = 33.57 kJ·mol−1). This result may be related to physical size or stronger interactions.

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.

On the estimation of the refractive index of heavy metal oxide glasses

The experimental values of the refractive index for more than ninety heavy metal oxide glasses are compared with those calculated using four methods: Hauser–Wenk equation (linear combination of dielectric constant), Lichtenecker logarithmic mixture rule, Wemple–DiDomenico and Lorentz–Lorenz equations. For the Lorentz–Lorenz field factor, a simple modification is suggested which relates this one to the ionicity of a glass.

Practical Feasibility of Arago-Biot and Lorentz-Lorenz Theory Through Variation of Refractive Index of Typical Binary Liquid Mixtures Employing Low-Cost Experimental Setup

Optical properties of the solutions comprising of two or more miscible liquids have been of immense interest both in the area of chemical and physical sciences. To date, there are reports on studies regarding different combinations of binary liquid mixtures. However, the experiments involved are either high-ended or using sophisticated instrumentation. Our prime objective is to set up a simple laboratory arrangement to estimate the refractive index of typical binary-liquid mixtures obtained by proportionate variations in combinations selecting from benzene, ethyl acetate, tetrahydrofuran, and water; without involving high-standard instrumentation or expensive laboratory setups. In the present study, we adopted a basic method to determine the refractive index of pure liquids of low polarity, like, benzene (C6H6) and tetrahydrofuran or THF (C4H8O) and of high polarities, such as ethyl acetate or EtOAc or EA (C4H8O2), and water (H2O) and also their binary homogeneous mixture with high accuracy. Our experimental data involving variation of refractive index with molar volume fraction matched very well with theoretical interpretations by Arago-Biot and Lorentz-Lorenz equation. In our results, density corrections have been neglected as we have chosen non-volatile solvents.

Performances of PMMA-Based Optical Fiber Bragg Grating Sensor in Extended Temperature Range

PMMA based optical fiber Bragg grating (POFBG) sensors are investigated in an environmental chamber with controlled temperature and relative humidity at temperature extended to 70 °C. At below a critical temperature of 50 °C the POFBG sensor exhibits good linearity and sensitivity for both temperature and humidity sensing. Nonlinear responses are observed at higher temperature, giving rise to varying, reduced magnitudes of sensitivities. An important feature of POFBG humidity sensing is observed at above critical temperature where the POFBG humidity sensitivity turns from positive to negative. A theoretical model based on Lorentz–Lorenz equation is presented to estimate the dependence of POFBG refractive index on temperature and relative humidity. The experimental results qualitatively agree with the theoretical analyses.