Elastic and inelastic angular distributions in the jz-conserving coupled states approximation for molecular collisions

An approximation scheme is described which allows the decoupling of molecular rotational j and l angular momenta in molecular collisions. With a particular choice of the interaction potential, the potential matrix couples only the molecular states of the system and in particular those in which the z-axis projection of j is conserved. Test calculations on He + H₂ for the elastic j = O → O and rotationally inelastic j = O → 2 differential cross sections are presented in the energy range 0.1 to 0.9 eV. These results are compared with the full coupled-channel cross sections and are found to be extremely accurate.     

Magnetic resonance imaging of soft tissue masses: an evaluation of fifty-three histologically proven tumors

Fifty-three histologically confirmed soft tissue masses in 48 patients were evaluated by magnetic resonance imaging (MR) and computerized tomography (CT). Twenty-three of these were malignant, twenty-three benign and seven of intermediate malignancy (all aggressive fibromatosis). The two procedures were compared for sensitivity and delineation of masses, their relationship to important neurovascular structures, their potential for histological diagnoses, their relative roles in influencing the surgical approach and the preferred modality in the follow-up for detection of tumor recurrence. Both modalities have their relative strengths and weaknesses. However, the superior contrast resolution of magnetic resonance imaging, its demonstration of lesions not clearly identified by CT, its pluridirectional capabilities and its ability to demonstrate large soft tissue tumors in a single coronal or sagittal plane makes it the preferred initial modality for evaluation of the soft tissue tumor of uncertain etiology and also in the follow-up of these patients. Despite MR's superiority in anatomically staging soft tissue tumors it, like CT, is of limited value in characterizing soft tissue sarcomas.     

Electocatalytic water oxidation by cobalt(III) hangman β-octafluoro corroles

Cobalt hangman corrole, bearing β-octafluoro and meso-pentafluorophenyl substituents, is an active water splitting catalyst. When immobilized in Nafion films, the turnover frequencies for the 4e(-)/4H(+) process at the single cobalt center of the hangman platform approach 1 s(-1). The pH dependence of the water splitting reaction suggests a proton-coupled electron transfer (PCET) catalytic mechanism.     

Transport and optical properties of heavily hole-doped semiconductors BaCu2Se2 and BaCu2Te2

Experimental and theoretical studies of the electronic and optical properties of orthorhombic BaCu₂Se₂ and BaCu₂Te₂ are reported. Experimental data include the electrical resistivity, Hall coefficient, Seebeck coefficient, thermal conductivity, and lattice constants for , and optical transmission and diffuse reflectance data at room temperature. Nominally stoichiometric, polycrystalline samples form with hole concentrations inferred from Hall measurements of 2×10¹⁸ and 5×10¹⁹ cm⁻³ near room temperature for the selenide and telluride, respectively. The corresponding mobilities are near 15 cm² V⁻¹ s⁻¹ for both materials. Optical measurements reveal a transition near 1.8 eV in BaCu₂Se₂, while no similar feature was observed for BaCu₂Te₂. First principles calculations indicate both materials are direct or nearly direct gap semiconductors with calculated gaps near 1.0 eV and 1.3 eV for the telluride and selenide, respectively, and predict weak absorption below about 2 eV. Transport properties calculated from the electronic structure are also presented.     

Auger transitions initiated from singly and doubly ionized states in Li metal

Major events in Auger spectra from Li surfaces containing both Na and K have been identified. Li Auger transitions initiated from both singly and doubly ionized K shells of Li have been observed. However, no higher energy satellite corresponding to the coupling of the energy of a plasmon decay with that of the Li K VV Auger electrons was detected.     

5,6-Dihydroxy-1,10-phenanthrolinium-1,10-ium dichloride

Abstract  

5,6-Dihydroxy-1,10-phenanthroline, obtained from recrystallization of a side-product of a condensation reaction between 1,10-phenanthroline-5,6-dione and 5,6-diamino-1,3-dimethyluracil, has been isolated as a dihydrochloride (C₁₂H₈N₂O₂·2HCl·0.5CH₃CN) by vapor diffusion of acetonitrile into an ethanol/HCl solution. The compound crystallizes in the triclinic space group P[`1] P\overline{1} with a = 5.8334(1) ?, b = 9.8041(2) ?, c = 11.9895(2) ?, α = 81.511(1)°, β = 76.395(1)°, γ = 81.429(1)°, and V = 654.48(2) ?³, Z = 2, R[F ² > 2σ(F ²)] = 0.028, and wR(F ²) = 0.078. The crystal packing is stabilized by two N–H⁺···Cl⁻ interactions (2.18(3) ?, 2.13(2) ?) and two O–H···Cl⁻ interactions (2.11(3) ?, 2.20(3) ?). Pi-stacking of the phenanthrolinium rings results in an interplanar distance of 3.431(5) ? with the phenanthrolinium ring centroids displaced from each other by ~6 ?. The results for this diprotonated species are compared to those reported by Lin et al. (Acta Cryst E65:o2367, 2009) for the monoprotonated form and this reveals the possibility of using the relative –OH/phenanthroline ring orientations as a qualitative diagnostic of metal–ligand interactions in metal complexes of this ligand (Larsson and Ohrstrom in Inorg Chim Acta 357:657, 2004; Guan et al. in Acta Cryst C64:m311, 2008).     

Photoabsorption cross section of titanium to cobalt

Calculations of the photoabsorption cross section of the elements TiCo are compared with recent measurements. The structure seen near the 3p ionization threshold is explained by the large 3p–3d oscillator strength and the short lifetime of the 3p hole due to a super Coster-Kronig transition.