Experimental and theoretical studies on IR, Raman, and UV-Vis spectra of quinoline-7-carboxaldehyde.

Spectroscopic properties of quinoline-7-carboxaldehyde (Q7C) have been studied in detail both experimentally and theoretically. The FT-IR (4000-50 cm(-1)), FT-Raman (4000-50 cm(-1)), dispersive-Raman (3500-50 cm(-1)), and UV-Vis (200-400 nm) spectra of Q7C were recorded at room temperature (25 °C). Geometry parameters, potential energy surface about CCH(O) bond, harmonic vibrational frequencies, IR and Raman intensities, UV-Vis spectrum, and thermodynamic characteristics (at 298.15K) of Q7C were computed at Hartree-Fock (HF) and density functional B3LYP levels employing the 6-311++G(d,p) basis set. Frontier molecular orbitals, molecular electrostatic potential, and Mulliken charge analyses of Q7C have also been performed. Q7C has two stable conformers that are energetically very close to each other with slight preference to the conformer that has oxygen atom of the aldehyde away from the nitrogen atom of the quinoline.

Vibrational spectra of quinoline-4-carbaldehyde: combined experimental and theoretical studies.

The FT-IR (4000-50 cm(-1)), FT-Raman (4000-50 cm(-1)) and Dispersive-Raman (3500-50 cm(-1)) spectra of solid sample of quinoline-4-carbaldehyde (Q4C) have been recorded. The molecule structure, vibrational frequencies, IR intensities, Raman intensities and thermodynamic properties of the two possible aldehyde rotamers of Q4C have been obtained with the Hartree-Fock (HF) and density functional B3LYP calculations employing the 6-311++G(d,p) basis set. Q4C has two stable conformers, in one of which the O atom of the aldehyde is oriented to form a H-bond with one of the hydrogens of quinoline, while in the other there is no such a H bond. The conformer with an extra H-bond is more stable and, thus it is the ground state. The computed vibrational frequencies of the lowest energy conformer agree also slightly better than those of the higher energy rotamer with the experimental frequencies after the computed frequencies are scaled. The temperature dependence of the standard heat capacities (C), standard entropies (S) and standard enthalpy (H) changes of Q4C has been discussed.

Determination of radioactivity and heavy metals of Bakirçay river in Western Turkey.

In this study, radioactive and heavy metal contaminations in sediments and waters of Bakirçay River in Western Turkey were investigated to determine their pollution potential. The radium concentrations in the water samples were measured using the collector-chamber method. The radioactivities of (40)K, (226)Ra and (232)Th in sediments and soils were found to be 45.30 to 839.19 Bq kg(-1), 35.26 to 160.57 Bq kg(-1) and 1.86 to 131.49 Bq kg(-1), respectively. The activity of (226)Ra in the water samples ranged from 0.09 to 0.36 Bq/L. To determine the radiological hazard of natural radioactivity in the samples, the external terrestrial gamma dose rate in air (n Gyh(-1)), annual effective dose rate (mSv y(-1)), radium equivalent activity (Bq kg(-1)) were calculated and compared with internationally recommended values.

Determination of structural and vibrational properties of 6-quinolinecarboxaldehyde using FT-IR, FT-Raman and dispersive-Raman experimental techniques and theoretical HF and DFT (B3LYP) methods.

The FT-IR (4000-50 cm(-1)), FT-Raman (4000-50 cm(-1)) and Dispersive-Raman (3500-50 cm(-1)) spectra of solid sample of 6-quinolinecarboxaldehyde (6QC) have been recorded. The structure, vibrational frequencies, IR intensities, Raman activities and thermodynamic properties of the two possible aldehyde rotamers of 6QC have been calculated at the Hartree-Fock (HF) and density functional B3LYP levels employing 6-311++G(d,p) basis set. The complete assignments were performed on the basis of the potential energy distribution (PED) of the all vibrational modes. Since HF and B3LYP mode definitions of this molecule are quite similar to each other, we only give in Table 3 PED of Rot1 calculated at B3LYP level for the sake of simplicity. Potential energy surface has been scanned over the C3-C2-C1O16 torsion angle. When the O atom of the aldehyde is farther away than the nitrogen atom of the quinoline, 6QC has the lowest possible energy, and thus is in its ground state. The scaled theoretical frequencies of the lowest energy rotamer agree also slightly better than those of the higher energy rotamer with the experimental frequencies. The thermodynamic characteristics of the ground state of 6QC have been theoretically investigated at 298.15 K temperature.

Theoretical and experimental studies on the vibrational spectra of 3-quinolinecarboxaldehyde.

Combined experimental and theoretical studies have been performed on the structure and vibrational spectra (IR and Raman spectra including far region) of 3-quinolinecarboxaldehyde. Hartree-Fock (HF) and density functional theory (DFT) B3LYP calculations have been employed with the 6-311++G(d,p) basis set for investigating the structural and spectroscopic properties of the Rot 1 and Rot 2 conformers of 3-quinolinecarboxaldehyde. The B3LYP frequencies are closer to the experimental frequencies than the HF frequencies, but scaled frequencies of both HF and B3LYP agree almost perfectly with the experimental frequencies. The Rot 1 conformer has been found more stable than the Rot 2 conformer. The scaled vibrational frequencies of Rot 1 conformer also agree slightly better than those of the Rot 2 conformer compared with the experimental frequencies. These indicate that 3-quinolinecarboxaldehyde has Rot 1 conformation in its ground state.

Combined experimental and theoretical studies on the vibrational spectra of 2-quinolinecarboxaldehyde.

Combined experimental and theoretical studies have been performed on the structure and vibrational spectra (IR and Raman spectra including far region) of 2-quinolinecarboxaldehyde. Hartree-Fock (HF) and density functional B3LYP calculations have been employed with the 6-311++G(d,p) basis set for investigating the structural and spectroscopic properties of two possible aldehyde rotamers of 2-quinolinecarboxaldehyde. When the O atom of the aldehyde is farther away than the nitrogen atom of the quinoline, 2-quinolinecarboxaldehyde has the lowest possible energy, and thus is in its ground state. The computed vibrational frequencies of this lowest energy rotamer agree also slightly better than those of the higher energy rotamer with the experimental frequencies after the computed frequencies are scaled.

Differential dose contributions on total dose distribution of (125)I brachytherapy source.

This work provides an improvement of the approach using Monte Carlo simulation for the Amersham Model 6711 (125)I brachytherapy seed source, which is well known by many theoretical and experimental studies. The source which has simple geometry was researched with respect to criteria of AAPM Tg-43 Report. The approach offered by this study involves determination of differential dose contributions that come from virtual partitions of a massive radioactive element of the studied source to a total dose at analytical calculation point. Some brachytherapy seeds contain multi-radioactive elements so the dose at any point is a total of separate doses from each element. It is momentous to know well the angular and radial dose distributions around the source that is located in cancerous tissue for clinical treatments. Interior geometry of a source is effective on dose characteristics of a distribution. Dose information of inner geometrical structure of a brachytherapy source cannot be acquired by experimental methods because of limits of physical material and geometry in the healthy tissue, so Monte Carlo simulation is a required approach of the study. EGSnrc Monte Carlo simulation software was used. In the design of a simulation, the radioactive source was divided into 10 rings, partitioned but not separate from each other. All differential sources were simulated for dose calculation, and the shape of dose distribution was determined comparatively distribution of a single-complete source. In this work anisotropy function was examined also mathematically.

The effect of magnetic field on a nonballistic spin field effect transistor.

A spin field effect transistor (FET) made of a nonballistic quantum wire with a single transport channel is considered in the presence of a magnetic field. The magnetic field includes either the externally applied field or the stray field due to ferromagnetic contacts used as injector and collector. When a magnetic field is applied the conductance fluctuations alter the spin precession and moreover spin flip occurs if the magnetic field is perpendicular to the Rashba field. Necessary conditions for a successful spin FET operation is obtained in the presence of a magnetic field.

Thermal, vibrational and EPR studies of Cu(II) bromide bis(p-methylaniline) and bis(m-methylaniline) complexes.

[CuBr(2)(pMA)(2)] and [CuBr(2)(mMA)(2)] complexes (pMA: p-methylaniline, mMA: m-methylaniline) have been prepared and characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, and IR, Raman and EPR spectroscopic studies. Coordination effects on the vibrational spectra of the ligands have been investigated. The room temperature EPR spectra of the complexes and their simulated spectra are also discussed in detail. The vibrational and EPR spectral studies suggest that the coordination sphere around Cu(II) consist of a distorted tetragonal structure.

Thermal studies and vibrational analyses of m-methylaniline complexes of Zn(II), Cd(II) and Hg(II) bromides.

The complexes having the MBr(2)L(2) (M: Zn, Cd and Hg; L: m-methylaniline) formulae have been prepared and characterized by their elemental analyses, thermogravimetric analyses, IR and Raman spectral studies. IR and Raman bands of the complexes have been assigned as compared with the free ligand. Coordination effects on the internal modes of m-methylaniline have been discussed. Vibrational spectra propose that the [ZnBr(2)(mMA)(2)] complex is in a tetrahedral environment around Zn(II) ion with C(2v) symmetry whereas Cd(II) and Hg(II) complexes have 5-coordinate polymeric bromide bridged structures.

Factor analysis applied to distribution of elements in western Turkey.

This paper examines the results of R-mode factor analysis performed on four radionuclides and two elements data from a geochemical survey from western Turkey. Sediment and soil samples numbering 321 were collected along the Gediz river and analysed for 238eU, 232eTh, 40K, 226Ra, Mg and Pb. Two factors in soil and sediment, which account for 59% and 56% of the total variance, respectively, were extracted and named as geological structure and volcano.

Density of states of disordered two-dimensional crystals with half-filled band

A diagrammatic method is applied to study the effects of commensurability in two-dimensional disordered crystalline metals by using the particle-hole symmetry with respect to the nesting vector P0 = +/-pi / a,pi / a for a half-filled electronic band. The density of electronic states (DoS) is shown to have nontrivial quantum corrections due to both nesting and elastic impurity scattering processes, and as a result the Van Hove singularity is preserved in the center of the band. However, the energy dependence of the DoS is significantly changed. A small offset from the middle of the band gives rise to the disappearance of quantum corrections to the DoS.