Temperature and concentration dependences of density and refraction of aqueous duloxetine solutions

Present paper reports the measured densities (ρ) and refractive indices (n _D) of aqueous solutions of Duloxetine drug in wide range of molal concentrations (m = 0.0101–0.1031 mol kg^?1) and at different temperatures (297.15, 302.15, and 307.15 K). Apparent molar volumes (φ_v) of drug were calculated from density data and fitted to Masson’s relation \((\phi _\nu = \phi _\nu ^0 + S_\nu ^* \sqrt c )\) and partial molar volumes (φ _v ⁰ ) were evaluated at different temperatures. Concentration dependence of refractive index (n _D = Kc + n _D ⁰ ) at experimental temperature has been studied. Density and refractive index data has been used for the calculation of specific refractions (R _D). Experimental (ρ and n _D) and calculated (φ_v, φ _v ⁰ , and R _D) properties have been interpreted in terms of concentration and temperature effects on structural fittings and drug-water interactions.     

Definition of invariant molecular tensors in an origin change. III. Comparison of the methods suitable for the obtainment of invariant tensors for refraction and the Faraday effect

In a previous paper, denoted I [C. Duprez and J. Tillieu, Int. J. Quantum Chem. 17 , 155 (1980)], a global tensor, invariant in an origin change, has been introduced for all optical phenomena. The results obtained have been applied to two particular cases: refraction and the Faraday effect, in Paper II [C. Duprez, Int. J. Quantum Chem. 17 , 169 (1980)]. In this paper, we study the various methods suitable for the calculation of these tensors. Then, we compare the results obtained in II with those previously obtained by other authors who, when studying the two particular cases mentioned above, omitted some terms necessary to obtain the invariance.     

Effective mass of an excess electron in fluids with high polarizability

The effective mass of an excess electron injected into a dense non-polar fluid with high polarizability is considered. The pseudopotential theory of electron interaction with a cellular fluid is used. Phase shifts of the p-scattering of an electron in a fluid are calculated. The Bardeen formula is used for the effective mass calculation. The density dependence of the effective mass in fluid xenon is compared with experimental data.     

Improved exchange-correlation potential for polarizability and dissociation in density functional theory

The authors propose a novel approach to the problem of polarizabilities and dissociation in electric fields from the static limit of the Vignale-Kohn (VK) functional. The response to the purely scalar part of the VK response potential is considered. This potential has ground-state properties that notably improve over the full VK response density and over usual (semi-)local functionals. The correct qualitative behavior of our potentials means that it is expected to work well for polarizabilities in cases such as the H(2) chain, and it will also correctly dissociate open-shell fragments in a field.     

Inverse relation between polarizability and valence-electron density at the nucleus

For the hydrogen atom, the usual result for the polarizability _H is rewritten here in terms of the electron density n(0) at the nucleus as _H = . Attention is then focused on an ion in a metal, say Na⁺ in condensed metallic sodium. Using a recent result of Blazej and March for the long-range polarization interaction between the ions, the polarizability is shown to depend directly on the inverse of the valence charge displaced by the ion in its metallic environment, again evaluated at the nucleus. A brief discussion is also given, but now involving a semiclassical Thomas-Fermi approximation, for divalent ions screened by bound-state s valence electrons.     

Molecular-scale model for the mass density of electrolyte solutions bound by clay surfaces: application to bentonites

A model to simulate the density of solutions adsorbed onto clay mineral surfaces is proposed. In this model, the alteration of the ionic distribution caused by the electric field associated with the surface charge of clay platelets is accounted for using an electrical triple-layer model with an overlapping diffuse layer. The combined effects of ion hydration and the electric field on the structure of water are introduced through their influence on the partial molar volume of water. This model, applied to Na-montmorillonite, simulates the distribution of the interplatelet solution density as a function of the distance to the mineral surface. High densities in the direct vicinity of the surface and slightly lower density (a few percent) than the normal density in the diffuse layer are obtained. These results show good consistency with the available data on bentonite and with the densities that can be inferred from molecular dynamics simulations. This model shows that the interplatelet distance plays an important role in the distribution of the mass density of the solution in the pore space of clay rocks.     

Analysis of anisotropic polarizability of molecules in the gas phase and in liquids and solutions

Conclusions The anisotropic polarizabilities of molecules in the gas phase and in dilute solutions in isotropic solvents, as determined from data on Rayleigh light scattering and the Kerr effect, are completely consistent with each other.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya No. 2, pp. 335–339, February, 1981.     

Effects of the polarizability and packing density of transparent oxide films on water vapor permeation

The tin oxide and silicon oxide films have been deposited on polycarbonate substrates as gas barrier films, using a thermal evaporation and ion beam assisted deposition process. The oxide films deposited by ion beam assisted deposition show a much lower water vapor transmission rate than those by thermal evaporation. The tin oxide films show a similar water vapor transmission rate to the silicon oxide films in thermal evaporation but a lower water vapor transmission rate in IBAD. These results are related to the fact that the permeation of water vapor with a large dipole moment is affected by the chemistry of oxides and the packing density of the oxide films. The permeation mechanism of water vapor through the oxide films is discussed in terms of the chemical interaction with water vapor and the microstructure of the oxide films. The chemical interaction of water vapor with oxide films has been investigated by the refractive index from ellipsometry and the OH group peak from X-ray photoelectron spectroscopy, and the microstructure of the composite oxide films was characterized using atomic force microscopy and a transmission electron microscope. The activation energy for water vapor permeation through the oxide films has also been measured in relation to the permeation mechanism of water vapor. The diffusivity of water vapor for the tin oxide films has been calculated from the time lag plot, and its implications are discussed.     

Density bifunctional theory using the mass density and the charge density

Can all the properties of a system composed of particles with masses, m _i , and charges, q _i , be determined from the charge density and the mass density? Subject to a small statistical caveat, this is true, and offers the prospect of an elegant extension of density-functional theory beyond the Born-Oppenheimer approximation.     

Global sensitivity analysis of chemical-kinetic reaction mechanisms: construction and deconstruction of the probability density function

This paper investigates global sensitivity analysis as applied to reaction mechanisms. It uses the HDMR (high-dimensional model representation) expansion and the features of the sensitivity indices to explore the probability density function (pdf) of predicted target outputs that results from the uncertainties in the rate coefficients. We study the autoignition of H(2)/O(2) mixtures, where the pdf describes the uncertainty in ignition delay times due to the uncertainties in the rate coefficients. The global sensitivity analysis in conjunction with the HDMR expansion allows for the deconstruction of the pdf in several different ways. These deconstructions allow the features of the pdf to be understood in terms of the constitute reactions in much finer detail than the study of a variance decomposition alone.     

Novel approaches for the prediction of density of glycol solutions

Two new approaches for the accurate prediction of densities of the commonly used glycol solutions in the gasprocessing industry are presented in the article. The first approach is based on developing a simple-to-use polynomial correlation for an appropriate prediction of density of glycol solutions as a function of temperature and weight percent of glycols in water, where the obtained results show very good agreement with the reported experimental data. The second approach, however, is based on the artificial neural networks （ANN） methodology, wherein the results demonstrate the ability of the introduced method to predict reasonably accurate densities of glycols under operating conditions. Comparisons of the two novel approaches indicated that the simple-to-use correlation appears to be superior owing to its simplicity and clear numerical background, wherein the relevant coefficients can be retuned if new and more accurate data are available in the future. The average deviation of the new proposed polynomial correlation results from reported data is 0.64 kg/m^3 whereas the average deviation of artificial neural networks （ANN） methodology from reported data is 1.1 kg/m^3.     

Determination of density and index of refraction of ozonides of sodium and potassium

Summary The densities and indices of refraction of sodium and potassium ozonides were determined.We consider it our pleasant duty to express our thanks to G. B. Bokii for assistance in the work.     

On molecular polarizability. 4. Evaluation of the ionization potential for alkanes and alkenes with polarizability

To express the influence of polarizability effect on ionization potential (Ip), the Geometric Mean Polarizability Effect Index (GMPEI) and Geometric Mean Polarizability Effect Index of pi Bond (GMPEIpi) were proposed for alkanes and alkenes, respectively. Taking a few of the compounds as a model, we obtained the correlation equations between the experimental Ip and GMPEI or GMPEI pi and then, with the obtained equations, we evaluated the Ip for the title compounds. The estimated Ip values by this work are in good agreement with the measured ones. Furthermore, the ab initio (#HF/6-31G** OPT, Gaussian 98 program) and semiempirical (AM1) Ip computation are finished, and other topological index correlations with the Ip of alkane are discussed.     

(Hyper)polarizability density analysis for open-shell molecular systems based on natural orbitals and occupation numbers

We have developed a method for analyzing the (hyper)polarizabilities of open-shell molecular systems. This method employs the (hyper)polarizability densities based on the natural orbitals and occupation numbers, which enables us to analyze the contributions of odd electrons having various open-shell (diradical) characters. Within broken-symmetry, i.e., spin-unrestricted, single-determinant molecular orbital and density functional theory approaches, we can also remove the spin contamination effects on these quantities through spin projection. To do that, an approximate spin projected method has been elaborated and applied to the analysis of the (hyper)polarizability of multi-radical systems. As examples, typical open-shell singlet systems, 1,3-dipoles and rectangular graphene nanoflakes, are examined.     

Relationships among R-matrix propagation,amplitude density function and invariant imbedding methods

It is shown that the basic relations of the R-matrix propagation method are equivalent to the recursive formulas of the invariant imbedding approach to the linear two-point boundary value problems. Both sets of recursive relations lead to first-order differential equations of identical form but associated with different initial conditions. From a purely theoretical viewpoint the R-matrix propagation method is found to be equivalent to the amplitude density function method of Secrest and Johnson. However, the former is superior to the latter in computational practice.     

Water density and polarizability deduced from the refractive index determined by interferometric measurements up to 250 MPa

The refractive index of water is precisely determined in the visible light range as a function of the pressure until 250 MPa by means of a new measurement device that uses a special pipe tee included in an interferometer set. This technique allows revisiting the Bradley-Tait and Sellmeier equations to make them dependent on the wavelength and the pressure, respectively. The Bradley-Tait equation for the pressure dependence of the water refractive index is completed by a wavelength-dependent factor. Also, in the considered pressure and wavelength ranges, it is shown that the Sellmeier coefficients can be straightforwardly linked to the pressure, allowing the determination of the refractive index of water for either any wavelength or pressure. A new simple model allows the determination of the density of water as a function of the measured refractive index. Finally, the polarizability of water as function of pressure and wavelength is calculated by means of the Lorentz-Lorenz equation.     

Effect of configurational composition of the wave function on calculated dipole polarizability of molecules

On the basis of the -electron approximation we have investigated the dependence of the calculated dipole polarizability of molecules on the configurational composition of the variational wave function. The values which were closest to the results of complex configurational interaction were obtained for sets including the single-determinant Hartree-Fock function and all the bonding doubly excited configurations constructed from the localized MO, and also from the complete set of singly and doubly excited configurations.Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 26, No. 1, pp. 70–73, January–February, 1990.