Synthesis of Novel Carbazole Fused Coumarin Derivatives and DFT Approach to Study Their Photophysical Properties

Novel coumarin derivatives have been synthesized by the classical Knoevenagel condensation of 4-hydroxy-9-methyl-9H-carbazole-3-carbaldehyde with active methylene compounds and characterized. Effect of solvent polarity on the photophysical properties, absorption and emission has been studied. The photophysical properties of the synthesized coumarins have been compared with some of the established analogous coumarin derivatives. Investigation of the structural parameters and understanding photophysical properties of the synthesized coumarin derivatives were carried out using Density Functional Theory (DFT) and Time Dependant Density Functional Theory (TDDFT) computations. The experimental values were correlated with the theoretical derived results. The ratio of the excited state and the ground state dipole moments was calculated by using solvatochromic and solvatofluoric data and compared with the values obtained from DFT and TDDFT computations.     

Electronegativity of fractionally charged atoms in the Density Functional Theory

The electronegativity (identified with the negative of the chemical potential) of atoms and ions has been calculated in several isoelectronic series using the Density Functional Theory. Then, the electronegativities of atoms and ions with fractional nuclear charge have been obtained by interpolation in each isoelectronic series. Similar interpolations have been performed, starting with approximate electronegativities obtained by Mulliken's finite difference approximation. Both sets of results have been compared.     

From the crust to the core of neutron stars on a microscopic basis

Within a microscopic approach the structure of Neutron Stars is usually studied by modelling the homogeneous nuclear matter of the core by a suitable Equation of State, based on a many-body theory, and the crust by a functional based on a more phenomenological approach. We present the first calculation of Neutron Star overall structure by adopting for the core an Equation of State derived from the Brueckner-Hartree-Fock theory and for the crust, including the pasta phase, an Energy Density Functional based on the same Equation of State, and which is able to describe accurately the binding energy of nuclei throughout the mass table. Comparison with other approaches is discussed. The relevance of the crust Equation of State for the Neutron Star radius is particularly emphasised.     

High resolutionMNN auger spectra of Ag,Cd, In,Sb, Te,and I

The strongest lines (M ₅ N _4,5 N _4,5 andM ₄ N _4,5 N _4,5) in theMNN Auger spectra of Ag, Cd, In, Sb, Te, and I have been investigated with high resolution by means of an electrostatic cylindrical spectrometer. The measured spectra have been found to have a fine structure corresponding to the splitting of the final states of the Auger transitionsM ₅ N _4,5 N _4,5 andM ₄ N _4,5 N _4,5. This has not been observed for these elements in spectra measured by the retarding field method. The line profiles are discussed.     

Conductivities and ion association constants of ferric chloride and chromic chloride in DMF and DMSO as a function of temperature

The equivalent conductivities of anhydrous ferric chloride (FeCl₃) and anhydrous chromic chloride (CrCl₃) were measured in nonaqueous aprotic solvents such as N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at temperatures between 278.15 and 318.15 K. In both DMF and DMSO, conductivity values for FeCl₃ were found to be higher than those for CrCl₃. In addition, the conductivity values for both FeCl₃ and CrCl₃ in DMF were higher than those in DMSO at all temperatures. The conductivity data were analyzed by the Robinson–Stokes equations. The limiting equivalent ionic conductivities for ferric ion (Fe³⁺) and chromic ion (Cr³⁺) and the ion association constants (K _A ) for FeCl₃ and CrCl₃ were determined in DMF and DMSO. The K _A values calculated for both FeCl₃ and CrCl₃ in DMF were higher than those in DMSO. This can be ascribed to an increase of the ion association constants with a decrease of the relative permittivity of solvents used in this study. The K _A values increased with the increase in temperature in the studied solvents. Thermodynamic functions (Gibbs’ free energy, entropy, and enthalpy of ion association) were estimated from the temperature dependence of the ion association constant. The positive values of entropy and enthalpy found for FeCl₃ and CrCl₃ at all temperatures indicate that the association process in DMF and DMSO is endothermic.     

On the determination of collision cross sections by nuclear Doppler shift

We report on measurements of the energy loss of ions in matter by “Inverted Doppler Shift Attenuation” (IDSA). This new method is an inversion of the “Doppler Shift Attenuation” (DSA) method for the determination of lifetimes of nuclear states. While in DSA the exact knowledge of the velocity dependent energy loss functiondE/ds is required, it is shown that in IDSA this function or the absolute collision cross section, respectively, can be determined from the Doppler spectrum of an excited nuclear fragment recoiling in matter, whose lifetime is known. No corrections or assumptions concerning the collision processes are necessary. ⁷Li^* fragments (E _γ=478 keV) from the¹⁰B(n, α)⁷Li^* reaction produce an easily observable and analysable Doppler spectrum. Here boron must be a constituent or an implanted impurity of the material to be investigated. The experimental set-up is described. An exact relativistic analysis of the Doppler spectrum is given. The measured collision cross sections turn out (a) to be proportional tov within the range 1.5 · 10⁸≦v≦4.8 · 10⁸ cm/sec, (b) are thus only due to pure “electronic” collisions, and (c) sensitively dependent on the charge distributions of the target atoms.     

Band structure of even-even selenium isotopes in the proton-neutron interacting Boson model

Available systematic IBM calculations [1-6] for Krypton and Strontium isotopes have been extended to Selenium. The analysis in terms of the IBM is complicated by the interplay of collective and noncollective degrees of freedom. However, satisfactory agreement has been obtained forN≦42.     

Luminescent properties of Eu2+ ions in AlN at low and high intensity of excitation

Luminescent properties of powder AlN∶Eu²⁺ phosphors were studied by excitation of 2-nd harmonic of ruby laser (hv=3·56 eV). It was shown that emission spectra of AlN∶Eu²⁺ phosphors consist of five or two overlapping bands according to the concentration of europium and the intensity of excitation. Decay times of luminescence of Eu²⁺ centres in different peaks lie between 0·9 and 1·5 μsec which is in agreement with the value of decay time of 4f⁶ 5d→47⁷ transition of Eu²⁺ ions. It is evident from the decomposition of emission spectra of Eu²⁺ centres that there exist several types of Eu²⁺ centres in AlN as was already demonstrated in the case of oxygen centres in AlN.     

Polylactic acid (PLA)/Silver-NP/VitaminE bionanocomposite electrospun nanofibers with antibacterial and antioxidant activity

The antibacterial property of silver nanoparticles (Ag-NPs) and the antioxidant activity of Vitamin E have been combined by incorporation of these two active components within polylactic acid (PLA) nanofibers via electrospinning (PLA/Ag-NP/VitaminE nanofibers). The morphological and structural characterizations of PLA/Ag-NP/VitaminE nanofibers were performed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy and X-ray diffraction. The average fiber diameter was 140 ± 60 nm, and the size of the Ag-NP was 2.7 ± 1.5 nm. PLA/Ag-NP/VitaminE nanofibers inhibited growth of Escherichia coli, Listeria monocytogenes and Salmonella typhymurium up to 100 %. The amount of released Ag ions from the nanofibers immersed in aqueous solution was determined by Inductively Coupled Plasma Mass Spectrometry, and it has been observed that the release of Ag ions was kept approximately constant after 10 days of immersion. The antioxidant activity of PLA/Ag-NP/VitaminE nanofibers was evaluated according to DPPH (2,2-diphenyl-1-picrylhydrazyl) method and determined as 94 %. The results of the tests on fresh apple and apple juice indicated that the PLA/Ag/VitaminE nanofiber membrane actively reduced the polyphenol oxidase activity. The multifunctional electrospun PLA nanofibers incorporating Ag-NP and Vitamin E may be quite applicable in food packaging due to the extremely large surface area of nanofibers along with antibacterial and antioxidant activities. These materials could find application in food industry as a potential preservative packaging for fruits and juices.     

Transient excited singlet state absorption in Rhodamine 6G

Transient excited singlet state absorption (ESSA) has been studied in Rhodamine 6G in ethanol using a nitrogen laser and nitrogen laser-pumped dye laser. Broad absorption with several submaxima and possible shoulders, which represent the vibrational structure, has been observed in Rhodamine 6G in the region, 4175–4640 Å. The position of the lowest vibrational level of the first excited singlet stateS ₁ has been determined from the crossing point of the long and short wavelength spectral wings of absorption and fluorescence respectively. The energy level scheme of the molecule has been obtained with the help of the absorption and fluorescence spectra recorded. The observed structure in ESSA has been tentatively interpreted to be due to transitions from the different vibrational levels ofS ₁ to one or more vibrational levels of the upper singlet electronic stateS ₄.     

Crystallographic,optical and magnetic properties of Eu2SiO4

The crystallographic properties of Eu₂SiO₄ are studied in terms of its isomorph Ca₂SiO₄. The recently discovered monoclinic room-temperature phase is ferroelastic and simultaneously ferromagnetic at low temperatures (T _e=5.40°K). The optical absorption and the dispersion properties have been measured in spectral intervals ranging from 0.5 to 3.6 eV and partly for temperatures between 300 and 500°K. This temperature range includes the ferroelastic-paraelastic phase-transition temperature (T _e=438°K). An anomaly of the dielectric constant atT _e suggests the presence of an unstable phase which would be ferroelectric. The Faraday rotation has been measured on either side of the absorption edge at 300 and 77°K. The recent results on crystal structure allow an explanation of the magnetic behaviour of the two ferromagnetic phases known up to now.     

Renormalons in QED

Four-dimensional Quantum Electrodynamics is studied in the limit of a large number of leptons (N→∞) up to terms of order 1/N inclusive. It is proven that closed analytic expressions can be given for the Borel transform of Green's functions. Furthermore, an appropriate renormalization scheme is introduced. In this scheme, up to first order in the 1/N expansion, all the renormalization group functions are polynomials. Since renormalon singularities are explicitly known, the Borel summability of QED is discussed.     

TheK Auger spectrum of the free magnesium atom

TheK Auger spectrum of free Mg atoms has been investigated with an electrostatic energy analyzer at an energy resolution of 0.16%. The ionization in theK shell of the Mg vapour was caused by electron impact. Absolute energies and relative intensities of the normal Auger transitionsK-LL and of the most intense satellite lines have been determined. The experimental energies and relative group intensities of the normal lines agree well with theoretical values. The total intensity of special classes of satellites are compatible with calculations of the shake theory within the sudden approximation.     

Repeated-Binge Ethanol Intoxication Leads to Lower Choline-Containing Compound Signals in Adult Rats: An In Vivo Marker of Ethanol-Induced Neurochemical Abnormalities

Ethanol is the most commonly abused intoxicating substance among young and middle-aged adults, and ranks highly as a cause of disability and mortality. A pattern of heavy consumption, called binge drinking, leads to various psychiatric disorders. However, to the best of our knowledge, assessments of the influence of short-term binge ethanol (SBE) intoxication on cerebral metabolite changes in human and rat models are scarce. We used in vivo ¹H magnetic resonance spectroscopy (¹H-MRS) to quantitatively assess neurochemical responses in hippocampus in a rat model of SBE intoxication. Seven SBE-exposed rats received an initial dose of 5.0-g/kg ethanol (30 %-w/v solution) through gavage and additional doses of 2.0-g/kg ethanol (25 %-w/v solution), every 8 hour for 4 days. Six rats in sham control group (CNTL) received an equivalent volume of distilled water at comparable times. Sixty minutes after last gavage session, in vivo ¹H-MRS scans were obtained from all rats using a 4.7 Tesla animal scanner. For neurochemical analysis, a single voxel was positioned in the hippocampal region and spectra were fitted for the quantification of 17 cerebral neurochemical signals. In hippocampus, the concentration of total choline-containing compound signals (tCho: [glycerophosphocholine] + [phosphocholine]) was significantly lower in SBE-exposed rats than in CNTL rats. Moreover, gamma-aminobutyric acid (GABA)/total creatine (tCr: creatine + phosphocreatine), tCho/tCr, and tCho/total N-acetyl-aspartate (tNAA: N-acetyl-aspartate + N-acetyl-aspartyl-glutamate) ratios were significantly lower in SBE-exposed rats than CNTL rats. We determined that tCho, GABA, and tNAA signals were highly sensitive to short-term binge ethanol intoxication, which provides insights into neurochemical alterations associated with ethanol abuse.     

Heat capacity of oxides in the Bi2O3-SiO2 system

The high-temperature heat capacity of Bi₄Si₃O₁₂, Bi₂SiO₅, and Bi₁₂SiO₂₀ has been investigated. It has been found that there is a correlation between the specific heat C _p ⁰ (298 K) and the composition of oxides in the Bi₂O₃-SiO₂ system.     

Preparation of n-ZnO/p-Si solar cells by oxidation of zinc nanoparticles: effect of oxidation temperature on the photovoltaic properties

In this study, n-ZnO/p-Si solar cells were fabricated by spraying ZnO nanoparticles (NPs) film synthesised by dissolving of high purity zinc in hydrogen peroxide H₂O₂ followed by thermal oxidation in air on p-type silicon substrates. The oxidation was carried out at different temperatures (200–500) °C. The crystalline structure of the ZnO NPs films was investigated by X-ray diffraction which indicated wurtzite structure films along (100) plane. The morphology of the NPs was studied by atomic force microscopy and scanning electron microscopy. The result showed an average grain size of ZnO NPs in the range of (72.7–95.8) nm and the surface roughness increasing with oxidation temperature. Three peaks located at ultraviolet, violet and green emission regions were noticed in the photoluminescence spectra of ZnO NPs. From optical studies, it was shown that the direct optical band gap is found to be in the range of (3.85–3.96) eV depended on the oxidation temperature. The synthesised ZnO films have n-type conductivity, and the mobility was in the range of (7–24) cm² V^?1 s^?1. Current–voltage I–V and capacitance–voltage C–V of ZnO NPs/Si heterojunction solar cell were investigated as function of oxidation temperature. The spectral response of n-ZnO NPs/p-Si solar cell showed two peaks of response and its maximum value approaching 0.62 mA W^?1 at λ = 800 nm. Solar cell oxidized at 500 °C gave open circuit voltage V _OC of 375 mV, short circuit current density J _SC of 25 mA cm^?2, a fill factor FF of 0.72, and conversion efficiency η of 6.79 % under illumination of 100 mW cm^?2.     

Recent Few-Nucleon Experiments and Discrepancies to be Solved

After ππ-exchange three-nucleon force (ππ3NF) was found in 1998, many experiments were made on 3N reactions and discrepancies between experiments and calculations with ππ3NF were reported. Origins of these remaining discrepancies have not been found yet. We briefly review experiments and the discrepancies in Nd scattering, Nd breakup and pd capture at intermediate energy, and review also recent systematic investigation on Space-Star anomaly and Quasi-Free Scattering anomaly in pd breakup at low energy.     

Search for correlation effects in theM 4, 5 N 4, 5 N 4, 5 Auger spectrum of xenon

TheM _{4, 5} N _{4, 5} N _{4, 5} Auger spectrum of xenon has been measured with high resolution. Theoretical line intensities and relative line energies for this spectrum have been calculated applyingjj coupling to the initial states and intermediate coupling and configuration interaction to the final states. Two facts indicate that correlation effects are only small in the present case: The application of configuration interaction gives only small changes in line intensities and the experimental line intensities are found to be in good agreement with theoretical results, calculated without configuration interaction.     

Non Locality Proofs in Quantum Mechanics Analyzed by Ordinary Mathematical Logic

The so-called non-locality theorems aim to show that Quantum Mechanics is not consistent with the Locality Principle. Their proofs require, besides the standard postulates of Quantum Theory, further conditions, as for instance the Criterion of Reality, which cannot be formulated in the language of Standard Quantum Theory; this difficulty makes the proofs not verifiable according to usual logico-mathematical methods, and therefore it is a source of the controversial debate about the real implications of these theorems. The present work addresses this difficulty for Bell-type and Stapp’s arguments of non-locality. We supplement the formalism of Quantum Mechanics with formal statements inferred from the further conditions in the two different cases. Then an analysis of the two arguments is performed according to ordinary mathematical logic.     

Analysis of the structure and magnetic properties of an interface in multilayered (Fe/Si) N nanostructures with the surface-sensitive XMCD method

The structural and magnetic properties of (Fe/Si) _N nanostructures obtained by successive deposition on the SiO₂/Si(100) surface at a temperature of the substrate of 300 K have been studied. The thicknesses of all Fe and Si layers have been determined by transmission electron microscopy measurements. The magnetic properties have been studied by the X-ray magnetic circular dichroism (XMCD) method near the Fe L _{3, 2} absorption edges. The orbital (m _l ) and spin (m _S ) contributions to the total magnetic moment of iron have been separated. The thicknesses of magnetic and nonmagnetic iron silicide on the Si/Fe and Fe/Si interfaces have been determined with the surface sensitivity of the XMCD method and the model of the interface between the nonmagnetic and weakened magnetic phases.